Steering Task Research Articles

Locomotor adjustments for circumvention of an obstacle in the travel path.

Independent living requires the navigation of a surrounding environment which is often cluttered with obstacles. When walking around an obstacle in the travel path, safe clearance requires some degree of body-segment reorientation. While body-segmental coordination strategies have been well studied for steering tasks that require moving the body in a new walking direction, it has never been established just what coordination strategies are used in different walking tasks. To address this issue, the current study was designed to investigate the timing of body segment coordination strategies and whole-body anticipatory locomotor adjustments employed when circumventing an obstacle placed in the travel path. Six healthy adults were asked to walk at their natural pace during unobstructed walking, as well as during avoidance to the right or left of a cylindrical obstacle (OBS) located in the travel path. Data analyzed were center of mass (COM) clearance from the OBS, forward velocity, step length and width, yaw angles of the head and trunk, roll angle of the trunk, and medial-lateral COM displacement. Onset of change in these variables from unobstructed walking was calculated as the time from OBS crossing. Avoidance involved two equally used strategies: lead limb close to or away from the OBS during the crossing step. Medial-lateral COM deviations were controlled by changes in step width without changes in trunk roll. There were no differences in the onset times of body segment reorientation for path deviation. These results are in contrast to previous studies on change in travel direction where the head segment initiates the body reorientation. Contrary to a steering task, circumventing an obstacle requires a different coordination for a transient change in COM trajectory with the underlying travel-direction maintained.

A recurrent network for landmark-based navigation.

A new type of network is proposed that can be applied to landmark navigation. It solves the guidance task, that is, it finds a nonvisually marked location using knowledge concerning its spatial relation to other, visible landmarks. The path to the searched location is not disturbed if a landmark is not visible for some time. The network can also describe findings obtained by experiments with insects and rodents, where the position of the landmarks has been changed after training. In this net, recognition does not occur by searching for a match between a pattern seen and the same pattern being stored but by searching for a match between a pattern seen with a prediction calculated from different data. A simple extension allows a unique match of the landmarks seen with the items stored in memory. With this extension a recognition of the individual landmark is not necessary. A specific output unit of the network can be interpreted in such a way as to show properties of place cells found in vertebrates and the function of the network proposed here as to determine the input to a place cell. The model can explain the observation that a given place cell can also be active when the animal moves in a different environment. An extension is discussed of how the network could be exploited for recognition-triggered response that allows animals to follow fixed routes.

An Information-Centered Analysis of the Tunnel-in-the-Sky Display, Part Two: Curved Tunnel Trajectories

A theoretical information-centered analysis that studies the effectiveness of the information presented by a tunnel-in-the-sky display in the aircraft guidance task of following curved trajectories is described. The analysis reveals important differences in the information as compared to the task of tracking straight trajectories investigated in a companion paper (Mulder, 2003). The optical gradients of perspective and compression that support pilot control behavior in straight tunnels are less useful in curved tunnels. First, curved trajectories yield no vanishing point or any other stationary optical invariant that can act as a reference for the change in the optical information. Second, only the optical gradients conveyed by the nearby elements of the tunnel provide valuable information about the aircraft locomotion. Third, due to the limitations of using a perspective display, the projection of a curved tunnel results in a biased pilot perception of the aircraft position and motion relative to the trajectory. The lower information-content of the display makes curved trajectories more difficult to follow than straight trajectories, deteriorating pilot path-following performance. A simulator experiment provides substantial evidence for these findings.

Bottom-Following for Remotely Operated Vehicles: Algorithms and Experiments

This paper addresses the problem of designing high precision bottom followers for remotely operated vehicles. In the framework of hierarchical control architectures able to uncouple the robot's kinematics (guidance) and dynamics (velocity control), the task of bottom-following is accomplished by suitable guidance task functions, which enable the system to handle unmodeled, i.e., not measured or estimated, kinematics interactions between the robot and the operating environment. In order to increase the bottom followers' reliability, the paper discusses possible techniques for modeling and handling the environmental and measurement uncertainty in the estimate of the local interactions between the vehicle and the operating environment, i.e., altitude and bottom slope. In particular, according to at-sea operational experience, the problem of managing dropouts due to erroneous tracking of multi-path echoes by the ROV altimeter(s) is addressed. Results of a large set of pool trials carried out with the Romeo ROV are reported and discussed.

Steering Robot for Evasive Maneuvers - Experiment and Analysis

In the pursuit of an objective rating on vehicle stability performance, it is always desirable to reduce disturbances during experimental evaluations, especially the ones introduced by human drivers. This paper presents the development of a steering robot designed for closed-loop steering tasks during evasive maneuvers. It describes the controller structure, discusses experimental results, followed by simulation/vehicle model verifications and theoretical control analysis.

Distinct nature of directional signals among parietal cortical areas during visual guidance.

We examined neuronal signals in the monkey medial superior temporal area (MST), the medial intraparietal area (MIP), and the lateral intraparietal area (LIP) during visually guided hand movements. Two animals were trained to use a joystick to guide a spot to a target. Many neurons responded in a direction-selective manner in this guidance task. We tested whether the direction selectivity depended on the direction of the stimulus spot or the direction of the hand movement. First, in some trials, the moving spot disappeared transiently. Second, the mapping between the hand direction and the spot direction was reversed on alternate blocks of trials. Third, we recorded the spot's movement while the animals moved the joystick and then played back that movement while the animals fixated without moving the joystick. Neurons in the three parietal areas conveyed distinct directional information. MST neurons were active and directional only on visible trials in both joystick-movement mode and playback mode and were not affected by the direction of hand movement. MIP neurons were mainly directional with respect to the hand movement, although some MIP neurons were also selective for stimulus direction. MIP neurons were much less active in playback mode. LIP neurons were active and directional in both joystick-movement mode and playback mode. Directional signals in LIP were unrelated to planning saccades. The selectivity of LIP neurons also became evident hundreds of milliseconds before the start of movement. Since the direction of movement was consistent throughout a block of trials, these signals could provide a prediction of the upcoming direction of motion. We tested this by alternating blocks of trials in which the direction was consistent or randomized. The direction selectivity developed earlier on trials in which the upcoming direction could be predicted. These results suggest that LIP neurons combine "bottom-up" visual motion signals with extraretinal, predictive signals about stimulus motion.

An Unexpected Role for Visual Feedback in Vehicle Steering Control

Some motor tasks can be completed, quite literally, with our eyes shut. Most people can touch their nose without looking or reach for an object after only a brief glance at its location. This distinction leads to one of the defining questions of movement control: is information gleaned prior to starting the movement sufficient to complete the task (open loop), or is feedback about the progress of the movement required (closed loop)? One task that has commanded considerable interest in the literature over the years is that of steering a vehicle, in particular lane-correction and lane-changing tasks. Recent work has suggested that this type of task can proceed in a fundamentally open loop manner, with feedback mainly serving to correct minor, accumulating errors. This paper reevaluates the conclusions of these studies by conducting a new set of experiments in a driving simulator. We demonstrate that, in fact, drivers rely on regular visual feedback, even during the well-practiced steering task of lane changing. Without feedback, drivers fail to initiate the return phase of the maneuver, resulting in systematic errors in final heading. The results provide new insight into the control of vehicle heading, suggesting that drivers employ a simple policy of "turn and see," with only limited understanding of the relationship between steering angle and vehicle heading.

Multifunction Radar: Task Scheduling

Multifunction radar has to perform several types of tasks. Some of them are systematic: the case of probing and guidance tasks. Others are random: the case when a new object is detected in the sky and should be confirmed and tracked. The tasks that consist of tracking targets are also random, since these targets may follow unexpected trajectories, possibly asking for a search in the neighborhood of the forecasted position of the target. The goal of this paper is to propose a strategy that maximizes the number of useful tasks performed, taking into account their priorities. The more efficient the radar, i.e. the higher the quality of the information provided, the greater the energy consumption, which leads to a reduction of the number of feasible tasks. Thus, the goal is to find a trade-off between energy consumption and the number of tasks to perform by unit of time that maximizes the quantity of useful information.

“ETL Spoken Dialog Corpus, Town Guidance Task, Japanese (1998)”-

“ETL Spoken Dialog Corpus, Town Guidance Task, Japanese (1998)”-

Bottom-following for remotely operated vehicles

This paper addresses the problem of designing high-precision bottom-followers for remotely operated vehicles. In the framework of hierarchical control architectures able to uncouple the robot's kinematics (guidance) and dynamics (velocity control), the task of bottom-following is accomplished by suitable guidance task functions, which enable the system to handle unmodeled, i.e. not measured or estimated, kinematics interactions between the robot and the operating environment. In order to increase the bottom-followers’ reliability, the paper discusses possible techniques for modeling and handling the environmental and measurement uncertainty in the estimate of the local interactions between the vehicle and the operating environment, i.e. altitude and bottom slope. In particular, according to at-sea operational experience, the problem of managing dropouts due to erroneous tracking of multi-path echoes by the ROV altimeter(s) is addressed. Results of a large set of pool trials carried out with the Romeo ROV are reported and discussed.

Snowplow Steering Guidance with Gain Stabilization

Acquisition and utilization of lateral guidance information is crucial for steering a vehicle. With practice, drivers can successfully perform the steering function using visual perception and hand-eye coordination. However, this seemingly simple task becomes difficult when the visual information loses its clarity. Driving a snowplow during whiteout conditions is one such example. In order to improve the safety and efficiency of snow removal operations, a supplemental guidance display was proposed and successfully implemented in a California Department of Transportation (Caltrans) snowplow. The guidance information was calculated based on the magnetic markers embedded in the roadway. The crucial step to this success is a transformation of the guidance display problem into a robust driver-in-the-loop control problem. This transformation considers the ‘display’ law as part of the overall driver-steering-control algorithm. Two key ‘assumptions’ for this design are (1) the ‘display’ law should be designed in such a way that drivers can use ‘proportional’ control gain alone to satisfy the performance and stability requirements of the steering tasks, and (2) the driver steering model can be described as a combination of gain and dynamic delay under the display law in (1). This paper describes the validation process for the ‘gain’ stabilization design concept as well as the associated driver steering model using the initial snowplow test data.

The Queuing Network Model Human Processor (QNMHP): An Engineering Approach for Modeling Cognitive Performance

Human performance modeling approaches (HPMAs) that are comprehensive and computational are particularly useful for system development. Current comprehensive approaches have strengths in modeling a person's actions, but lack mathematical foundations that inherently yield information about the time and capacity related performance of the human in the system. This paper proposes a complementary approach called the Queuing Network Model Human Processor (QNMHP) that combines elements of the GOMS/Model Human Processor approach with the mathematical concept of queuing networks. A general queuing network representing the human and methodology for using this network are discussed in light of current efforts to model a steering task.

Comparison of the effects of sleep deprivation, alcohol and obstructive sleep apnoea (OSA) on simulated steering performance

Patients with obstructive sleep apnoea (OSA) are reported to have an increased risk of road traffic accidents. This study examines the nature of the impairment during simulated steering in patients with OSA, compared to normal subjects following either sleep deprivation or alcohol ingestion. Twenty-six patients with OSA and 12 normal subjects, either deprived of one night's sleep or following alcohol ingestion [mean ( SD) alcohol blood level 71.6 mg dl −1(19·6)], performed a simulated steering task for a total of 90 min. Performance was measured using the tendency to wander ( SD), deterioration across the task, number of ‘off-road’ events and the reaction time to peripheral events. Control data for OSA, sleep deprivation and alcohol were obtained following treatment with nasal continuous positive airway pressure (nCPAP), after a normal night of sleep, and following no alcohol, respectively. Patients with untreated OSA, and sleep-deprived or alcohol-intoxicated normal subjects performed significantly less well, compared to their respective controls ( P<0·01 for all tests), with untreated OSA lying between that of alcohol intoxication and sleep deprivation. Alcohol impaired steering error equally throughout the whole drive, whilst sleep deprivation caused progressive deterioration through the drive, but not initially. Untreated OSA was more like sleep deprivation than alcohol, although there was a wide spread of data. This suggests that the driving impairment in patients with OSA is more compatible with sleep deprivation or fragmentation as the cause, rather than abnormal cognitive or motor skills.

Cognitive Neurorehabilitation

Back to table of contents Previous article Next article Book Forum: Neuropsychiatry and NeurologyFull AccessCognitive NeurorehabilitationSANJAY GUPTA, M.D., SANJAY GUPTASearch for more papers by this author, M.D., Olean, N.Y.Published Online:1 Apr 2001https://doi.org/10.1176/appi.ajp.158.4.670AboutSectionsView EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail Brain dysfunction and resulting problems afflict a large number of patients and their families. These problems may occur following a variety of processes including normal aging, stroke, and degenerative conditions such as Alzheimer’s disease. This book is a comprehensive review of cognitive rehabilitation, bridging the various issues from basic science to clinical outcome. Theoretical concepts and methodological issues are reviewed systematically. It also provides a view of the future of cognitive neurorehabilitation, presenting the concept of “smart houses” that will use technology to help patients with altered brain function live independently.This book provides an updated review of the concept of brain plasticity. In reading the first chapter I realized that there was a considerable degree of new information on the degree of brain plasticity. There is an excellent presentation of injury-related structural changes, including the concept of increasing connections of the surviving neurons. The book provides evidence to link dendritic growth with functional recovery. These new concepts, although quite complex in nature, are presented in an easy to understand fashion.The chapter on intracerebral transplantation presents a powerful strategy to study plasticity and regeneration in the brain. Various techniques used in this area, such as animal models, lesion models, and fetal tissue implants, are discussed with reference to the cholinergic system in the brain. Despite the fact that these techniques are still in the experimental stages, the book provides hope and insights into the future.Neuroimaging is a technique that has greatly improved our understanding of brain function in the recent past and continues to provide new insights into the brain. This book presents the application of neuroimaging to cognitive neurorehabilitation.I was particularly impressed by the chapter on the psychosocial environment and the elderly, which presents practical strategies for reversing age-associated cognitive decline that could be applied to the aging population. This chapter presents a rehabilitation program that includes a psychosocial component to enhance feelings of control, cognitive training to teach practical strategies, and activities for overall well-being. These programs, in conjunction with those described in other chapters in the book focusing on training techniques to improve cognitive function in neurological patients, have significant potential for use in relatively healthy older adults.I found the chapter on memory rehabilitation in the elderly and brain-injured people and the chapter on rehabilitation of executive disorders to be so fascinating that I skipped to them first. I think they would benefit clinicians from various disciplines. Techniques for improving problem-solving abilities, attention, and awareness are discussed very well. There is focus on the caregiver, an important component in the planning of care for these patients.Traumatic brain injury accounts for the major share of costs for rehabilitation of neurological injuries in the United States. Chapter 18 presents the dilemma professionals face today between cost criteria and the lack of clear clinical guidelines and the fear that cost might prevail as the driving force in selection of those who receive rehabilitation. The importance of secondary mood disorders in patients with brain dysfunction is also presented in this book; these disorders need to be addressed for a comprehensive management of these patients.High technology has been harnessed to improve the quality of life for patients with brain dysfunction. The use of “smart houses” was news to me. Technology is used in such houses to maintain independence for patients with cognitive impairments. The concept of a “neuro-page,” a simple portable paging system that reminds memory-impaired individuals to complete certain tasks, was also interesting to learn about. The interactive task guidance system provides a set of cues to guide subjects through everyday tasks. This book gives an excellent overview of these concepts in the section dealing with brain-injured people.This book is not exactly light reading, but it is easy to understand. It requires that attention be paid to the concepts presented, so they can be assimilated and used. Overall, the information in this book is excellently organized and covers the wide range of issues involved in cognitive neurorehabilitation. This book will be of immense value to professionals and paraprofessionals working in the area of cognitive deficits following brain dysfunction. It will be particularly useful to occupational therapists and physiotherapists, neurologists, psychiatrists, psychologists, neuroscientists, and those involved with basic science research.Edited by Donald T. Stuss, Gordon Winocur, and Ian H. Robertson. New York, Cambridge University Press, 1999, 385 pp., $110.00. FiguresReferencesCited byDetailsCited ByNone Volume 158Issue 4 April 2001Pages 670-671 Metrics History Published online 1 April 2001 Published in print 1 April 2001

Sonar-based guidance of unmanned underwater vehicles

This paper addresses the problem of the design and coordination of guidance and sonarbased motion estimation algorithms for unmanned underwater vehicles. In the framework of a two-layered hierarchical architecture uncoupling the system's dynamics and kinematics, a couple of guidance laws for approaching a target with the desired orientation and following an environmental feature have been designed with Lyapunov-based techniques. Suitable acoustic-based estimators of the corresponding operational variables have been designed and integrated with the guidance and control system. A finite state machine combined with a suitable interface for event generation allows the coordinated execution of basic guidance and motion estimation tasks to carry out more complex functions. Experimental results of pool trials of a prototype unmanned underwater vehicle executing free-space maneuvering, wall-following tasks and the more complex mission of following the perimeter of the trial pool are reported and discussed.

PM—Power and Machinery: Prediction and Experimental Verification of the Hoe Path of a Rear-mounted Inter-row Weeder

Accurate lateral positioning of implements operated by tractors is important in field operations such as inter-row weeding and band spraying. However, this can be difficult to achieve in practice and consequently there is much interest in automating the steering task. To develop an effective integrated system of control, the dynamic lateral behaviour of the tractor and implement must be understood.In this paper, a mathematical model is developed to predict the path of the weeder mounted on a tractor three-point linkage with free lateral movement and supported on steerable wheels. Experiments were conducted with a unit which could be steered either mechanically or by an electro-hydraulic control system. The principal purpose of the experiments was to test model performance and assess the steering geometry needed to achieve the best weeding accuracy. Results show good agreement between the performance of the test machine and the mathematical model. The amplitude of the predicted path was accurate within 2% and the phase angle within 2° in all but extreme tractor steering errors. Results also indicate that the level of steering accuracy sufficient for a commercial inter-row weeder can be achieved with simple proportional control. An optimum steering gain of 2·9 is suggested for the electro-hydraulic unit.

A Review and Reappraisal of Task Guidance: Aiding Workers in Procedure Following

Procedures can greatly benefit workers at tasks such as inspection, maintenance, and assembly. Procedures may serve as a guideline for expert workers or they may provide a list of directives to be followed exactly; either way, procedures serve to structure a task, to aid worker memory, and to guarantee consistency and safety. Light, inexpensive electronics may allow for the development of task guidance systems to further help workers by presenting procedures and associated information about the task. This article reviews the current state of knowledge about the development of task guidance systems, and highlights their potential value in a variety of domains. First, the characteristics of procedural tasks are discussed, as a basis for a discussion on the benefits of procedure following that task guidance systems can support, and potential problems in procedure following that task guidance systems can mitigate. Then, current research results in task guidance systems are summarized. Finally, a discussion is...

Bottom-Following for Remotely Operated Vehicles

This paper addresses the problem of designing high precision bottom followers for remotely operated vehicles. In the framework of hierarchical control architectures able to uncouple the robot’s kinematics (guidance) and dynamics (velocity control), the task of bottom-following is accomplished by suitable guidance task functions, which enable the system to handle unmodelled, i.e. not measured or estimated, kinematics interactions between the robot and the operating environment. In order to increase the bottom followers’ reliability, the paper discusses possible techniques for modeling and handling the environmental and measurement uncertainty in the estimate of the local interactions between the vehicle and the operating environment, i.e. altitude and bottom slope. In particular, according to at-sea operational experience, the problem of managing dropouts due to erroneous tracking of multi-path echoes by the ROV altimeters) is addressed. Results of a large set of pool trials carried out with the Romeo ROV are reported and discussed.

Reducing Over-Reliance on Task-Guidance Systems

Task-guidance systems are unsensored, computer-based systems that remind a user of the actions required to complete a task. These systems have various forms, including electronic procedures. Over-reliance, which has been documented as an issue with automation and decision-aiding systems, may also be a problem for task-guidance systems, despite their passive nature. This paper describes task-guidance systems and over-reliance on task-guidance systems as background, and then provides the results of a study into reducing this over-reliance on task guidance systems and thereby improving performance.

Advanced Vehicle Navigation applied in the BMW Real Time Light Simulation

Advanced vehicle navigation based on the US Global Positioning Systems (GPS) will play a major role in future vehicle control systems. Contemporary vehicle navigation systems generally consist of vehicle positioning using satellites and location and orientation of the vehicle with respect to the roadway geometry using a digitised map on a CD-ROM. The standard GPS (with Selective Availability) enables positioning with an accuracy of at least 100 m and is sufficiently accurate for most route guidance tasks. More accurate, precision navigation can be obtained by Differential GPS techniques. A new light concept called Adaptive Light Control (ALC) has been developed with the aim to improve night-time traffic safety. ALC improves the headlamp illumination by means of continuous adaptation of the headlamps according to the current driving situation and current environment. In order to ensure rapid prototyping and early testing, the step from offline to online (real-time) simulation of light distributions has been successfully completed in the driving simulator. The solutions are directly ported to real vehicles to allow further testing with natural road conditions.