An optimal reconfiguration control scheme based on control allocation CA is proposed to stabilize the yaw dynamics of the tractor-semitrailer vehicle. The proposed control scheme is a twolevel structure consisting of an upper level of sliding mode yaw moment controller SMYC and a lower optimal brake force distributor BFD . The upper SMYC is designed to follow the tractor yaw rate and the combin...

Low-cost GPS receivers provide geodetic positioning information using the NMEA protocol, usually with eight digits for latitude and nine digits for longitude. When these geodetic coordinates are converted into Cartesian coordinates, the positions fit in a quantization grid of some decimeters in size, the dimensions of which vary depending on the point of the terrestrial surface. The aim of this...

A capture-mark-recapture study was conducted in crop fields in Morogoro, Tanzania, to investigate how the population dynamics of multimammate field rats, Mastomys natalensis, was influenced by the commonly practised land preparation methods and cropping systems. Two land preparation methods (tractor ploughing and slash and burn) and two cropping systems (mono-cropping with maize and inter-cropp...

To ensure that a liquid tank semi-trailer has good yaw stability and path-following performance on low-adhesion roads under turning conditions, multi-object PID differential braking-control method is proposed, which takes the tractor rate, articulation angle as control parameters. According to principle of equivalence, trammel pendulum (TP) model used simulate sloshing effect in tank, Fluent so...

This article documents the extent of children's involvement in tractor operations among a representative sample of Kentucky children living and working on family farms. Specifically, we describe children's exposures to tractor-related work activities, profile their use of the tractor (number of days worked), and assess compliance with generally recommended safety measures, such as using tractor...

This paper presents a method to develop a system, which will enable an autonomous agricultural vehicle to follow a leading vehicle with a given lateral and longitudinal offset. With the aid of the RTK GPS systems the position of the leading tractor was obtained every 500 ms with accuracy in the range of centimeters. To provide the target position for the guidance of the following agricultural v...

Power hop is a “porpoising” type of pitch/bounce oscillation superimposed on the forward motion of tractors equipped with pneumatic tires. It is most often observed with tractors having two powered axles pulling towed implements in moderate to high draft field operations on dry soils. As power hop begins, the tractor exhibits gradually increasing vibration amplitudes until the operator, of nece...

The vibration conditions to which tractor operators are subjected are complex and varied with multi axis translation and rotational vibration inputs to different parts of the body. Working under such conditions may lead to human fatigue and other driving related hazards. The present research was carried out to study the operators under varying conditions of vibration while driving a tractor wit...

A Bessel beam without an axial gradient can exert a pulling force on an object [A. Novitsky, C. W. Qiu, and H. Wang, Phys. Rev. Lett. 107, 203601 (2011)]. However, it cannot be called a "tractor beam" per se, as long as the light pulling effect is ultrasensitive to the object's material and size, a perturbation of which will make the optical traction go away. In this Letter, we investigate and ...