Steering Mode Research Articles

Is a multi array-contact lead able to improve STN-DBS in Parkinson’s Disease?

Background Multi-directional electrodes in STN-DBS give the possibility to steer the high frequency current into the direction for clinical improvement and moreover recording of multi-array local field potential recordings (LFPs) give the possibility to determine the spatiotemporal distribution of oscillatory power across the STN that is related to the symptomatology in PD patients. Ultimately this information can be used as a feedback to optimize the stimulation parameters. Methods Eight PD patients were included in the study. After micro-electrode recording (MER), to determine the boundaries of the STN, temporarily a prototype of a new 32-contact DBS lead was inserted during the DBS procedure. Different modes of current steering were employed to improve motor symptoms and patients were scored on beneficial and adverse effects. Prior to and immediately after stimulation the distribution of spectral power was recorded by LFPs and spatiotemporal changes were evaluated with Fourier analysis. Results Thresholds of the effects of spherical stimulation were comparable to thresholds of stimulation through the conventional electrode at the same location in 89% of the cases. In eight of fourteen side effects, steering stimulation current increased the threshold for side effects by ⩾ 1 mA compared to spherical stimulation. The size of the therapeutic window could be widened in patient 6, 7 and 8 by steering stimulation in the posterior, posterior and anterior direction, respectively. LFP recordings prior to stimulation yielded the boundaries of the STN by showing increased spectral power particularly in the 13–40 Hz range. Recordings across all directions showed distinct spatiotemporal patterns of neuronal activity, which were related to the pattern of stimulation and the PD symptoms of the patient. Conclusions With a new DBS lead it is possible to steer stimulation current in STN-DBS such that it leads to a larger therapeutic window than with conventional spherical stimulation. Simultaneous LFP recordings across the entire STN provide spatial information about the location of the STN and its disease-related electrical activity. This may potentially be of benefit in predicting how to steer the current towards the sensorimotor part, while avoiding adverse effects.

Steering Control Strategies for a Four-Wheel-Independent-Steering Bin Managing Robot

Abstract: Automatic steering systems are a standard function for robotic agricultural equipment. Ackerman steering is the most common type of steering mechanism on such equipment, making them perform as car-like vehicles. Because of their kinematic constraints, it is quite difficult to maneuver carlike vehicles effectively in orchards due to confined working space, constrained by physical boundaries such as tree rows and other obstacles. To remove such technical difficulties, more sophisticated steering mechanisms and steering control strategies are required for robotic agricultural equipment. In order to conveniently manage fruit bins in confined tree aisles constrained by high density tree rows, a robotic bin management system, called bin-dog system, implementable in typical Washington State tree fruit orchards has been developed. This bin-dog system adopted a four-wheel-independent-steering (4WIS) mechanism as the solution to achieve the necessary drivability and maneuverability. To provide adequate controllability to this 4WIS, a four-mode steering strategy, including Ackermann steering, active front and rear steering (AFRS), crab steering, and spinning, were designed for this bin-dog to manage fruit bins effectively in the confined orchard space. This control system makes it possible for the bin-dog system to switch between four steering modes using the most appropriate steering mode to complete all maneuvering tasks in a most effective way. To design such a control system, it is important to understand the influence of major factors, such as longitudinal speed and control gain on performance under different steering modes when tracking various paths. In this paper, a pure pursuit method was implemented using a GPS-based navigation to evaluate auto-steering performance with both Ackermann steering and AFRS modes. Field tests were conducted to assess the navigation performance using different steering strategies when tracking different paths. The results indicated that by properly selecting a steering strategy for the situation, it is possible to achieve a satisfactory path tracking performance for tracking curvy paths or completing tasks such as merging and cornering.

Implementation of an Auto-Steering System for Recreational Marine Crafts Using Android Platform and NMEA Network

This paper deals with development of an autopilot system for leisure yacht based on NMEA 2000 network and android platform. The developed system can operate both for manual steering and automatic navigation mode. In automatic steering mode, after manipulation of commands which are NMEA 0183 sentences by android platform, the developed system translates and sends the packets through NMEA 2000 network. Then the controller which is connected to NMEA 2000 network receives the commands and controls the boat’s rudder system automatically. The automatic steering mode is achieved by cooperation of two controllers; one for controlling the rudder system, and the other for controlling the vessel’s heading. To control the vessel’s rudder and heading angle two PID controllers are developed with an adjustable dead-band gain. Also, in order to eliminate the steady-state error occurred by applying dead-band, an integral controller which specifically supervises the system’s behavior inside the dead-band area is developed. In this paper, at the first stage, simulations are accomplished using computer in order to examine the feasibility of the proposed based on simulation results. In the next step, the system on a real hydraulic steering model is implemented and at the end the performance examination by implementing it on a real boat and doing test navigation is executed.

Experimentations on the adaptive sliding mode control for a trajectory tracking applied on a bi-steerable car

Chattering is known as the most important drawback of sliding mode control (SMC). The latter is robust against external perturbations and model incertitude. The objective of this paper is to provide adaptive SMC laws allowing control of a complex system while avoiding or reducing chatter effects. The controlled system is called Robucar, it is a four wheel mobile robot car in double steering mode also called a bi-steerable car (Bis-Car). It is a non-holonomic, non-linear and under-actuated system. A robust adaptive SMC law is designed to reduce the chatter effect while keeping the robustness properties. The robustness and the applicability of the control laws are shown in simulation tests first, and then in experimental tests where perturbations are considered by introducing errors on the initial position, the traction velocity and the steering angle.

2P01 Curving performance improvement by mechanical pneumatic steering system (Shotgun Session)

In order to decrease the lateral force generated in the railway vehicles in the curving sections, a simple steering system for the bolsterless bogie was developed. It is a simple steering bogie system that does not adopt complex bogie structure, and considered to be equipped with the function which prevents reverse steering movement. The most important feature of the developed system is that the system controls the steering force by the relative mechanical movement between the bogie and the car body that pass curving sections. That is, it is not based on the electrical control; the authors have designated this system as a "mechanical pneumatic steering system". This system is composed of pneumatic actuators that are built into mono-links, a mechanical sensing device of the bogie angle made by the relative movement between the bogie and the car body, and a pneumatic valve that works according to the sensing device. The sensing device for mechanical detection of the bogie angle is composed of two universal joints and a connecting rod that is expandable and contractile, but not revolvable. This device is able to transfer only the relative yawing angle between the car body and the bogie, and the other movement can be canceled by the motion of joints and the connecting rod. The mechanical pneumatic steering system with such features has been applied to a test bogie, and fundamental running tests were carried out in the test line in Railway Technical Research Institute. As a result, it is found that the average lateral force in a circular curve section with a radius of 160(m) is decreased by about 80% compared with the case where the steering control is not applied. In addition, we confirmed the basic safety of the reverse steering mode, which causes the controller failing.

A Study on Control System for Four-Wheels Independent Driving and Steering Electric Vehicle

The structure and principle of four-wheels independent driving and steering (4WIS-4WID) electric vehicle are presented firstly, and on this basis the structure of network control system base on CAN bus is built. Kinematics and dynamics models of typical steering modes (such as all wheel steering, front (rear) wheel steering, parallel steering, zero-radius steering) are built, and the control strategy is presented. The experimental results show that the control system structure and control algorithm are effective.

Heart Rate Variability in Response to Task Automation in Agricultural Semi-Autonomous Vehicles

The goal of this study was to assess the sensitivity of the heart rate variability measure to variations in task difficulty and drivers' mental workload in agricultural semi-autonomous vehicles. 30 young participants with at least one year of tractor driving experience performed steering and implement control and monitoring tasks in a simulator study. Experiments were conducted using the tractor driving simulator (TDS) located in the Agricultural Ergonomics Laboratory at the University of Manitoba. Five levels of automation support from low to high were defined for the implement control and monitoring task. One-half of the participants performed a manual steering task while the other half drove the TDS in automatic steering mode, which only required them to monitor a mapping system and supervise the computer that was performing the steering task. A heart rate monitor was used to record the participants' heart rate. Time and frequency domain parameters of heart rate were analyzed. Some of the time and frequency domain parameters showed some sensitivity to workload variations, however, inconsistencies were observed in the results. The widely used HRV parameter, 0.1 Hz component of HRV, was not sensitive enough to differentiate mental workload levels when the drivers were involved in the task-loop.

Directional steering: A novel approach to deep brain stimulation.

The aim of this study was to investigate whether directional steering through a novel 32-contact electrode is safe and can modulate the thresholds for beneficial and side effects of stimulation. The study is a single-center, performance and safety study. Double-blind intraoperative evaluations of the thresholds for therapeutic benefit and for side effects were performed in 8 patients with Parkinson disease while stimulating in randomized order in spherical mode and in 4 different steering modes with the 32-contact electrode, and in monopolar mode with a commercial electrode. In addition, simultaneous recordings of local field potentials through all 32 contacts were performed. There were no adverse events related to the experimental device. For 13 of 15 side effects (87%), the threshold could be increased by ≥ 1 mA while steering in at least one direction in comparison to conventional spherical stimulation, thereby increasing the therapeutic window by up to 1.5 mA. Recording local field potentials through all 32 electrode contacts yielded spatiotemporal information on pathologic neuronal activity. Controlled steering of current through the brain may improve the effectiveness of deep brain stimulation (DBS), allow for novel applications, and provide a tool to better explore pathophysiologic activity in the brain. This study provides Class IV evidence that for patients with Parkinson disease, steering DBS current is well tolerated, increases the threshold for side effects, and may improve the therapeutic window of subthalamic nucleus DBS as compared with current standard spherical stimulation.

Role of thermal noise in tripartite quantum steering

The influence of thermal noise on bipartite and tripartite quantum steering induced by a short laser pulse in a hybrid three-mode optomechanical system is investigated. The calculation is carried out under the bad cavity limit, the adiabatic approximation of a slowly varying amplitude of the cavity mode, and with the assumption of driving the cavity mode with a blue detuned strong laser pulse. Under such conditions, explicit expressions of the bipartite and tripartite steering parameters are obtained, and the concept of collective tripartite quantum steering, recently introduced by He and Reid [Phys. Rev. Lett. 111, 250403 (2013)], is clearly explored. It is found that both bipartite and tripartite steering parameters are sensitive functions of the initial state of the modes and distinctly different steering behavior could be observed depending on whether the modes were initially in a thermal state or not. For the modes initially in a vacuum state, the bipartite and tripartite steering occur simultaneously over the entire interaction time. This indicates that collective tripartite steering cannot be achieved. The collective steering can be achieved for the modes initially prepared in a thermal state. We find that the initial thermal noise is more effective in destroying the bipartite rather than the tripartite steering which, on the other hand, can persist even for a large thermal noise. For the initial vacuum state of a steered mode, the tripartite steering exists over the entire interaction time even if the steering modes are in very noisy thermal states. When the steered mode is initially in a thermal state, it can be collectively steered by the other modes. There are thresholds for the average number of the thermal photons above which the existing tripartite steering appears as the collective steering. Finally, we point out that the collective steering may provide a resource in a hybrid quantum network for quantum secret sharing protocol.

Residents, customers or citizens? Tracing the idea of youthful participation in the context of administrative reforms in Finnish public administration

In parallel with developing participatory policies, public administration in Finland and elsewhere has undergone constitutive administrative reform. By analysing policy documents and civil servants’ experiences, we ask how meta-level administrative steering modes manifest themselves in the motives and goals set for participation and what kinds of political agencies they allow for children and young people who play a pivotal role in the future shape of democracy. We conclude that coexisting different steering modes produce different practical solutions that define the content of “citizenship” in different ways. What is essential is the reflectivity concerning whether one or another steering mode dominates participation policy, and with what consequences.

Research on the Cornering Characteristics of Three-Axle Vehicle

A multi-axle dynamic steering technology was proposed to solve the steering stability and maneuverability problem of heavy vehicle. Two degrees of freedom linear steering-model and motion-equations of three-axle vehicle was established. Taking the zero sideslip angle as the control target and the proportional rear-front wheel angle as control method, we got the angular scale-factor equation and related matrix of the state space and transfer function. The MATLAB software was used to simulate the different steering modes stability steady-state and transient response. The results show that by using proportional control method the sideslip angle can be stabilized near zero and by using multi-axle dynamic steering technology the stability and maneuverability of the vehicle when steering can be improved effectively.

Hybrid Organizations in Social Service Delivery in Quasimarkets

With the introduction of quasimarket principles in the mid-1990s, the German social service sector faced several challenges from above (the state), within (the organizations), and outside (new competitors and “players”). Within the social services, considerable differences prevail between subsectors; although all reforms have been oriented at the principle of (quasi)markets, the governance arrangements implemented have been rather divergent across subfields. This article compares the effects of the introduction of quasimarket principles in two subfields with very different governance architectures: youth welfare and old-age care. Basic findings include different degrees and variants of hybridity at the meso-level of local welfare arrangements as well as at the micro-level of the organizations in the field. The analysis shows a considerable effect of different governance regimes on the openness of the subfields to new competitors (profit-oriented and voluntary), the reactions of established third sector organizations (internal reforms and hybridization), and the modes of political steering (with varying degrees of informality and oversight).

Study on Electronic Differential Control for a Mini Electric Vehicle with Dual In-Wheel-Motor Rear Drive

An electronic differential control system (EDS) has been designed based on a mini electric vehicle (EV) with dual in-wheel-motor rear drive. In view of imperfection of current strategy with speed and moment as control variables, a new control strategy for EDS in a two in-wheel-motor drive EV is proposed with the moment of driving wheel torque as control variable and the slip rate equilibrium of two driving wheels as control objective, considering the effects of axle load transfer. The differential control experiments are conducted with steering mode and straight acceleration mode based on the vehicle prototype. The results show that the control strategy is reasonable, and the controller can effectively realize EV electronic differential by coordinating the moment of two driving wheels.

Gestión de innovación: la estrategia para lograr posicionamiento y crecimiento financiero en las empresas familiares de la industria de la imprenta en Colombia

This reflection paper, derived from the research “Analysis of the Innovation Management in Business Success: Application to Family Businesses in the Graphics Sector in Colombia” which begins in 2010 and comes both of the counseling to a company in the industry, and of the thesis to qualify for the title of Master in Management of the Universidad Militar Nueva Granada, aims to reflect on the Colombian printing and publishing industries, deepening the steering and evolution modes of the innovation model. Emphasis is placed on the family businesses, studying their features from the financial analysis of the companies. According to this, the printing and related industries are formed mainly by family businesses that have maintained a tradition in their managerial staff, some of which have several generations of activity. This industry has received a special boost in recent decades, favored by the development of technology and communication, which has enabled it to expand its spectrum of activity to other sectors and markets with innovative products.

Urban Governance and its Impact on the Role Perception and Behaviour of European City Councillors

The trend towards new forms of political steering at the local level is a matter of fact that has been demonstrated in numerous studies. Thereby, the development is not one-dimensional, but produces a variety of different types of urban governance. Presumably, the empiric trend towards new forms of political steering changes the political power structure and the roles of relevant actors in local politics. The present article assesses the implications of different models of urban governance on the significance and the behaviour of the city councillors. Drawing on the MAELG survey on European city councillors, the hypothesis of whether the political relevance of the city council is lower under new forms of governance due to the inclusion of private actors and a new allocation of functions and political roles is tested. Furthermore, it is assumed that municipal councillors consequently display specific communication patterns and network strategies to enhance or restore their influence in local politics. The results of the multilevel analyses are only partly in line with the theoretic assumptions. The main hypothesis that the implementation of new urban steering modes generally weakens the councillors' position of power must be rejected. Different kinds of urban governance arrangements have unequal effects on the political relevance of the city councillors, and new steering instruments often strengthen the influence of the municipal council. Apparently, the institutional organisation of urban governance matters to a large extent. Regarding networking activities, the councillors evidently adapt their communication strategies to the present urban governance model. The empirical findings corroborate the hypothesis that municipal councillors pursue specific network strategies according to the prevailing governance context by expanding their ties with the respective key players. Furthermore, the frequency of communication has a positive impact on the significance of the council in local politics. City councillors who are in close contact with relevant local actors clearly feel more influential in local decision-making processes.

Study on the Steering Performance of Dual-Motor Drive Track Bulldozer

The driving theory and the dynamic characteristics of small radius steering, medium radius steering and big radius steering is analyzed, and the simulation model is established under Matlab/Simulink. Then the track bulldozers steering performance of the three sheerings is simulated. The results show that, at different steering modes, the running states of the two sides driving motors are not the same, and the track driving forces of the two sides vary widely. The track driving force is great in the small radius steering model, while small in the medium and big radius steering models. The simulation results lay the foundation for dual-motor drive track bulldozers steering performance matching.

Design of Electric Orchard Vehicle Four-Wheel Steering Control System

Nowadays, the operation of orchard vehicle which is used in China has the disadvantages such as single function poor automation level etc. Therefore, it can hardly adapt to the complex environment in orchard. The electric vehicle that powered by electrical drive motor can not only save energy, but also achieve the goal of controlling more conveniently and efficiently. Some electrical vehicles in China can take a variety of steering modes. However, most orchard vehicles lack of targeted terrain design. Electric four-wheel independent drive and steering vehicles have strongly strengthened this weakness. This paper uses four-wheel independent drive & four-wheel independent steering structure and completes the design of the control system. The aim is to achieve five different orchard vehicle driving modes which based on microcontroller system, real-time feedback and achieve differential speed calculating model through the multi-channel sensor in the steering modes. Thus, it can ensure the slip angle within the allowable range and driving stability. It also proposes the design & manufacturing of wireless remote control device and operation panel in order to simplify drivers operation and increase the efficiency.

Experimental tests of a sliding mode controller for trajectory tracking of a car-like mobile robot

SUMMARYThis paper deals with the problem of the practical tracking control of an experimental car-like system called the Robucar. The car-like Robucar is a four-wheeled car in a single steering mode. Based on a kinematic model of the car-like Robucar, a practical tracking controller is designed using the second-order sliding mode control of the super twisting algorithm. Hence, the output tracking of the desired trajectory is achieved, and the tracking errors vanish asymptotically. Experimental tests on the car-like Robucar are presented for simple and real-time nonholonomic trajectories, and comparative results with the conventional sliding controller demonstrate the applicability and efficiency of the proposed controller.

Performance analysis of azimuth electronic beam steering mode spaceborne SAR

Pointing angle and pattern of the antenna can be changed swiftly to actualize the azimuth beam scanning by using electronic beam steering, which makes the Synthetic Aperture Radar (SAR) system more flexible and achieve a high resolution or cover a long strip within short time span. When the pointing angle is steered away from boresight, some aberrations may appear on the antenna pattern, e.g., the grating lobe appears, the main lobe gain decrease, and antenna pattern broadens, e.g., the aberrations result in the worsening of system performance, and complicate the corresponding performance analysis method. Conventional computation methods of performance parameters do not account for the rapid change of the antenna pattern. It introduces remarkable errors when the scanning angle is large. In this paper, a method of calculating performance parameters is proposed for the beam steering mode, which achieves the parameters by the energy accumulation in time domain. Actually, the proposed method simulates the working process of SAR and obtains accurate performance parameters. Furthermore, we analyze the effects of the grating lobe on the Azimuth Ambiguity to Signal Ratio (AASR), and present the generic Pulse Repetition Frequency (PRF) choosing principle which can also prevent the ambiguous area from weighting by the grating lobe. Finally, the effect of the antenna configuration on the performance parameters is analyzed by a system example.

Complex Orthogonal Decomposition Applied to Nematode Posturing

The complex orthogonal decomposition (COD), a process of extracting complex modes from complex ensemble data, is summarized, as is the use of complex modal coordinates. A brief assessment is made on how small levels of noise affect the decomposition. The decomposition is applied to the posturing of Caenorhabditis elegans, an intensively studied nematode. The decomposition indicates that the worm has a multimodal posturing behavior, involving a dominant forward locomotion mode, a secondary, steering mode, and likely a mode for reverse motion. The locomotion mode is closer to a pure traveling waveform than the steering mode. The characteristic wavelength of the primary mode is estimated in the complex plane. The frequency is obtained from the complex modal coordinate's complex whirl rate of the complex modal coordinate, and from its fast Fourier transform. Short-time decompositions indicate the variation of the wavelength and frequency through the time record.