This research studied the tractive performance of integrated steering-drive systems by investigating a two-wheel-drive vehicle having two independent rear drive wheels and non-driven steerable front wheels. The feasibility of integrating the steering and drive systems and the performance advantages that may be obtained was investigated. In order to demonstrate the feasibility of the concept, the steering system and the drive system of a test vehicle were integrated using a computer with a specially-developed program. The software algorithm developed for the program used the mathematical relationship between the rear drive wheel speeds and the steer angles of the non-driven front wheels to set the steer angles. A test-bed vehicle was fitted with instrumentation to implement the computer-integrated system. The circuitry of the hydraulic lines of the hydraulically-driven test vehicle was modified to allow changes in drive configuration. These changes are not possible with conventional vehicles. The test vehicle could be configured for the following steering-drive configurations: open differential rear drive with steerable front wheels, independent rear drive wheels with front castors, locked differential rear drive with steerable front wheels and the computer-integrated steering-drive system developed. The sensors on the vehicle allowed data collection for characterising the vehicle and wheels. omputer models were developed for the various steering-drive configurations from the force relationships, longitudinal slip relationships, vehicle geometry and turning geometry. Characteristics of the test vehicle's wheels for use in the models were measured experimentally. he models were used to simulate the behaviour, and calculate the tractive performance, of the four steering-drive configurations in various situations but actual tests were not able to be conducted with the available resources. Unlike previous models, the models of this research used force and longitudinal slip information rather than power input and power output to produce values for drawbar efficiency. theoretical analysis was conducted into the optimal slip conditions for maximum tractive efficiency. The analysis was conducted using a more rigorous mathematical analysis than previous researchers and used a thorough graphical analysis to substantiate the mathematical analysis. Previous studies concluded that under all traction conditions the efficiency of slip will be a maximum when the slip of each wheel is equal. This research revealed that, contrary to the previous literature, efficiency of slip will not be a maximum when the slip of each wheel is equal under non-uniform traction conditions. The simulations were focussed on turning situations, non-uniform traction conditions and traversing slopes. The optimal slip conditions and steer angles for turning situations were also investigated and analysed. The computer-integrated steering-drive system achieved a drawbar pull 50% higher than that for a conventional open differential when undertaking a 10 m radius turn with non-uniform traction conditions. Under these conditions, the drawbar efficiency of the computer-integrated steering-drive system was 5% greater than that for the open differential at the lower drawbar pull. It was concluded that it is feasible and beneficial to use a computer-integrated steering system. Vehicles using such a system would operate more effectively and efficiently when turning under load, moving across slopes and in non-uniform traction conditions. More effectiveness was provided through greater drawbar pull and higher drawbar efficiency. / thesis (PhD)--University of South Australia, 2005.

This research studied the tractive performance of integrated steering-drive systems by investigating a two-wheel-drive vehicle having two independent rear drive wheels and non-driven steerable front wheels. The feasibility of integrating the steering and drive systems and the performance advantages that may be obtained was investigated. In order to demonstrate the feasibility of the concept, the steering system and the drive system of a test vehicle were integrated using a computer with a specially-developed program. The software algorithm developed for the program used the mathematical relationship between the rear drive wheel speeds and the steer angles of the non-driven front wheels to set the steer angles. A test-bed vehicle was fitted with instrumentation to implement the computer-integrated system. The circuitry of the hydraulic lines of the hydraulically-driven test vehicle was modified to allow changes in drive configuration. These changes are not possible with conventional vehicles. The test vehicle could be configured for the following steering-drive configurations: open differential rear drive with steerable front wheels, independent rear drive wheels with front castors, locked differential rear drive with steerable front wheels and the computer-integrated steering-drive system developed. The sensors on the vehicle allowed data collection for characterising the vehicle and wheels. omputer models were developed for the various steering-drive configurations from the force relationships, longitudinal slip relationships, vehicle geometry and turning geometry. Characteristics of the test vehicle's wheels for use in the models were measured experimentally. he models were used to simulate the behaviour, and calculate the tractive performance, of the four steering-drive configurations in various situations but actual tests were not able to be conducted with the available resources. Unlike previous models, the models of this research used force and longitudinal slip information rather than power input and power output to produce values for drawbar efficiency. theoretical analysis was conducted into the optimal slip conditions for maximum tractive efficiency. The analysis was conducted using a more rigorous mathematical analysis than previous researchers and used a thorough graphical analysis to substantiate the mathematical analysis. Previous studies concluded that under all traction conditions the efficiency of slip will be a maximum when the slip of each wheel is equal. This research revealed that, contrary to the previous literature, efficiency of slip will not be a maximum when the slip of each wheel is equal under non-uniform traction conditions. The simulations were focussed on turning situations, non-uniform traction conditions and traversing slopes. The optimal slip conditions and steer angles for turning situations were also investigated and analysed. The computer-integrated steering-drive system achieved a drawbar pull 50% higher than that for a conventional open differential when undertaking a 10 m radius turn with non-uniform traction conditions. Under these conditions, the drawbar efficiency of the computer-integrated steering-drive system was 5% greater than that for the open differential at the lower drawbar pull. It was concluded that it is feasible and beneficial to use a computer-integrated steering system. Vehicles using such a system would operate more effectively and efficiently when turning under load, moving across slopes and in non-uniform traction conditions. More effectiveness was provided through greater drawbar pull and higher drawbar efficiency. / thesis (PhD)--University of South Australia, 2005.

The countersteering effect in motorcycles describes the apparent need to steer in the wrong direction in order to cause the chassis of the vehicle to lean over in the required direction just prior to executing a turn. The inherent danger with this procedure is that in a emergency situation where a motorcyclist must execute a sudden swerve to avoid a collision, the required behaviour is counterintuitive and panic may cause the rider to make the wrong initial movement thereby reducing their chance of avoiding a collision. As the importance of the countersteering effect is not taught in UK motorcycle training courses, the current work has attempted to establish whether doing so could significantly improve the ability of riders in swerve to avoid manoeuvres. An initial survey of motorcycle riders suggested some confusion about the nature of countersteering. To explore this further, four groups of riders with different levels of experience and training: novice, experienced, advanced and expert, were tested over a simple swerve to avoid course that was based on the procedure in the current UK motorcycle test. All the riders used the same motorcycle with on-board instrumentation to record the steering effort and the response of the machine. The tests were also videoed to gain extra information about rider behaviour. The results suggest that those riders that had been trained in exploiting countersteering were better able to avoid the obstacle and significantly better at returning the machine to the desired path thereby avoiding a potential secondary collision. It appeared that those riders who had learned by experience were still not proficient when faced with a sudden swerve to avoid scenario.

Single Gimbal Control Moment Gyroscopes (CMGs) are thought to be efficient actuators for the attitude control of the new generation of small and agile satellites. CMGs belong to a class of actuators known as momentum exchange devices. This thesis presents a detailed formulation of three-axis attitude dynamics and control of a satellite equipped with a cluster of n momentum exchange devices (which include CMGs and reaction wheels).

A novel method of beam steering that utilizes a mass-produced Digital Micromirror Device (DMD) enables a large field of view and reliable single chip Light Detection and Ranging (LIDAR). Using a short pulsed laser, the micromirrors' rotation is frozen mid-transition which forms a programmable blazed grating which efficiently redistributes the light to a single diffraction order, among several. With a nanosecond 905nm laser and Si avalanche photo diode, measurement accuracy of < 1 cm for 3340 points/sec is demonstrated over a 1 m distance range and with a 48° full field of view.

La recherche a montré que les enseignants se réfèrent à un sous-ensemble délèves, le steering group, pour piloter leur enseignement (planification y comprise). Alors que les résultats de certains auteurs montrent que lenseignement est calibré sur les faibles, dautres études indiquent que ce sont les forts qui sont pris en compte. Cette thèse de doctorat rassemble sept articles qui se penchent sur le phénomène de steering group. Les sept articles sont organisés en trois parties. La première combine deux articles de revue de littérature portant sur les processus de pensée des enseignants lors de la planification et de linteraction en classe. La problématique du steering group y est située dans les processus de gestion de dilemmes de la part des enseignants. Après une partie plus méthodologique, une partie empirique rassemble quatre articles portant sur ce même phénomène. La pertinence de lhypothèse de la mise en dilemmes est quantitativement vérifiée (150 enseignants primaires) : les enseignants se posent-ils la question des élèves sur qui centrer lenseignement dans le cadre de la gestion des programmes officiels : les forts ou les faibles ? Ensuite, la manière dont les enseignants utilisent leur(s) steering group(s) est analysée dans des études qualitatives (10 enseignants primaires). Les résultats des différentes études montrent, dune part, que lhypothèse de la mise en dilemme peut être conservée et, dautre part, que la gestion de la classe va au-delà dune affaire de forts ou de faibles. Les enseignants centrent leurs interventions sur les forts en appliquant des stratégies de compensation réservées aux faibles et inversement. Enfin, les sept articles sont mis en perspectives dans une discussion qui propose diverses ouvertures de recherches portant sur lanalyse des processus décisionnels des enseignants ainsi que sur le développement et lévolution de leurs croyances et connaissances psychopédagogiques. / Research has shown that teachers refer to a subgroup of pupils, named steering group, to pace their teaching (planning thought processes included). While some researchers have shown that teachers refer to the low performance pupils, some other have shown that the high performers are taken into account. Seven articles focussed on the steering group phenomenon are regrouped in this doctoral dissertation. These seven articles avec organised in three main areas. The first area is theoretical and presents two literature reviews concerning the teacher thought processes during planning and teaching interaction in the classroom. The steering group phenomenon is situated in the thought processes teachers are engaged when they manage teaching dilemmas. After an article dealing with methodological issues, an empirical area is presenting four articles focussed on the steering group phenomenon. The relevance of the dilemma management by teachers is quantitatively analysed (150 elementary teachers): are teachers concerned with the question on which pupils to focus instruction regarding to progression in the official curriculum: low or high performers? The manner teacher use their steering group(s) is then analysed in some qualitative studies (10 elementary teachers). Results show, on the one hand, that the dilemma management hypothesis could be maintained and, on the other hand, that classroom management goes beyond focussing on the high or low performers. Teachers pace their instruction for the high performers, while implementing compensation strategies for the low performers, and inversely. Finally, the seven articles are discussed to suggest different research perspectives concerning teachers decision making processes and the development and evolution of their knowledge and beliefs.

All-terrain vehicle(ATV) is very popular in Europe and North America because of its excellent riding performance. The Design of suspension and steering mechanism is one of the most important parts in ATV design, because it is much related to the riding performance of ATVs. Therefore, this research focuses on investigating the design of suspension and steering mechanism for ATVs. There are two main objectives to be achieved in this research. One is to build the analysis theory, and the other is to develop a systematic design process of suspension and steering mechanism for ATVs. Firstly, we survey papers about suspension and steering mechanism to find its basic functions and properties. Secondly, we use engineering design method to classify the design requirements and frame the design process. Thirdly, we list new suspension and steering mechanisms by applying the creative mechanism design procedure, then separate the new mechanisms separate into two types. One type is suitable only for back-wheel drive vehicles, and the other type is suitable for back-wheel drive and four-wheel drive vehicles. Finally, we complete the kinematic design of the type1.1(double-wishbone) and type8.3(new mechanism) suspension and steering mechanisms based on the Genetic algorithm (GA), and we can obtain the better mechanism dimensions than Yamaha 660 and 450 ATV.

This thesis investigates the design and evaluation of a control system, that is able to adapt quickly to changes in environment and steering characteristics. This type of controller is particularly suited for applications with wide-ranging working conditions such as those experienced by small motorised craft. A small motorised craft is assumed to be highly agile and prone to disturbances, being thrown off-course very easily when travelling at high speed 'but rather heavy and sluggish at low speeds. Unlike large vessels, the steering characteristics of the craft will change tremendously with a change in forward speed. Any new design of autopilot needs to be to compensate for these changes in dynamic characteristics to maintain near optimal levels of performance. This study identities the problems that need to be overcome and the variables involved. A self-organising fuzzy logic controller is developed and tested in simulation. This type of controller learns on-line but has certain performance limitations. The major original contribution of this research investigation is the development of an improved self-adaptive and predictive control concept, the Predictive Self-organising Fuzzy Logic Controller (PSoFLC). The novel feature of the control algorithm is that is uses a neural network as a predictive simulator of the boat's future response and this network is then incorporated into the control loop to improve the course changing, as well as course keeping capabilities of the autopilot investigated. The autopilot is tested in simulation to validate the working principle of the concept and to demonstrate the self-tuning of the control parameters. Further work is required to establish the suitability of the proposed novel concept to other control.

Thesis (M.S. in Mechanical Engineering) Naval Postgraduate School, March 1997. / Thesis advisor, Fotis A. Papoulias. Includes bibliographical references (p. 83). Also available online.

In this work torque vectoring methods are used to compensate for a low performance steer-by-wire system. Currently a number of vehicle manufacturers are considering introducing steer-by-wire into their range of vehicles. Some of the key concerns for the manufacturers are safety and cost. The safety can be subdivided in the integrity of the steering system and the effect on handling. The focus of this study is the use of low cost steering actuators on a vehicle and identify its effects on the vehicle's handling response. The test vehicle is dune buggy modified to accommodate the low performance steer-by-wire system without a direct mechanical link between the steering wheel and the wheels and equipped with various sensors to data recording. In order to investigate the influence of torque vectoring system on the steer-by-wire, an eight degrees of freedom vehicle model in Matlab/Simulink has been developed. The eight degrees of freedom are longitudinal and lateral translations, yaw and roll motion and rotation of each wheel. The Matlab/Simulink model also includes the dynamics of the actuators, which is validated against the experimental data. The actuator was shown to have a bandwidth of less than 0.3 Hz. The eight degrees of freedom model's response was validated against experimental data for both steady state and transient response up to 0.5 g. The tyre forces and moments are implemented by using the Dugoff tyre model, which has been validated against experimentally measured data. The torque vectoring system uses the cascade approach based on a reference model, which uses a two degrees of freedom (bicycle model) to generate the reference signal for control purposes. The upper level yaw controller is based on the optimal control theory and uses the LQR (Linear-quadratic regulator) approach. The lower level wheel slip controller is based on a slidingmode structure and prevents tyre force saturation. The simulation results show that the vehicle augmented with the torque vectoring system outperforms the low performance steer-by-wire vehicle and also the vehicle with conventional steering arrangement.