Straight Travel Research Articles

Design, simulation, and experimental investigation on a novel robot fish driven by piezoelectric bimorphs

The efficient swimming performance of fish is a miracle of nature, and the bionic robot fish powered by smart materials can replicate the movement pattern of fish to a greater extent. To achieve a simple, flexible, and controllable underwater robot, a novel robot fish driven by piezoelectric bimorphs is proposed in this study, which has similar swimming patterns to the body and/or caudal fin propulsion swimming mode and can achieve straight travel and steering underwater. The validity and feasibility of the principles were verified by wet mode simulation. A prototype is manufactured and tested for underwater vibration characteristics to confirm the motion pattern of the caudal fin of the robot fish. It weighs 13.3 g, a length of 150 mm. The maximum uniform speed of the robot fish prototype is 53 mm s−1, the thrust is 2.213 mN, and its maximum efficiency is 0.864%.

Navigation and control development for a four-wheel-steered mobile orchard robot using model-based design

Autonomous agricultural robots play an essential role in agricultural mechanization. Self-reliable navigation of these robots is a challenging task. Generally, Global Navigation Satellite Systems (GNSS) based approach, combined with other sensors, is mainly utilized for robot navigation. However, these navigation methods encounter trouble during GNSS signal outages and require a stable navigation solution. This paper proposes a stable navigational algorithm for an orchard robot based on the model-based design that works in a GNSS denied environment. The designed model takes the input driving coordinates and vehicle state from wheel and steering encoders and translates them into vehicle navigational command. The navigation model is built in MATLAB/Simulink environment. The dynamic behavior of the model is neglected, considering that the robot is a slow-moving vehicle due to its application requirement. For robot navigation, the control command given by the controller is divided into velocity and steering control that follows a defined path at a given velocity and steering rate. The developed system is verified both in real and simulation environments. The control algorithm is verified using a mobile robot (non-holonomic) in an outdoor environment. It is confirmed that the robot is able to navigate satisfactorily in the given environment with normalized root mean square difference error within the range of 0.2–0.4 for steering offset at turning and 0.05 degrees during straight travel. Similarly, the model correlation lies close to 0.99 compared to the steering input angle. The proposed navigational model gives a realistic approach for vehicle navigation with the least sensor interaction.

Design of a Small Sweeping Robot Based on STM32

With the continuous improvement of people’s living standards and the emergence of various intelligent appliances, a household floor sweeping robot is designed in this subject, which can automatically clean the ground in the room. The robot takes STM32F103ZET6 single chip microcomputer as the controller, uses two DC motors and L298N driving chips to drive the robot to walk, and uses ultrasonic sensors to detect indoor obstacles, The infrared sensor is used to detect the indoor edge position, the straight travel control of the robot is realized through the coding disk combined with PID algorithm, and the turning control is realized through differential control and PWM speed regulation. The robot can realize the garbage cleaning in the regular room, and has a certain application prospect.

A Path Tracking Method for Autonomous Rice Drill Seeder in Paddy Fields

For the purpose of overcoming the obstacles in application of autonomous rice drill seeder in paddy fields, a path tracking algorithm with high accuracy used for steering control during straight traveling in uneven muddy paddy fields is introduced in this paper. Combining lateral deviation and heading angle deviation as feedback, a nonlinear steering control model is developed in the algorithm. To avoid the position error caused by incline, the influence brought by the roll angle and the pitch angle of the vehicle on position coordinates are taken into account when the vehicle is on a slant. The experiments carried out in arable paddy fields show that the mean absolute lateral deviation of the algorithm was less than 2.9 centimeters and the heading angle deviation was less than 0.03°. The path tracking algorithm is able to meet the required precision for autonomous rice drill seeder in paddy fields of China.

Ergonomic evaluation of standard and alternative pallet jack handless

AimTransportation of materials using a pallet jack pulled behind the operator is common due to the visual advantages while transporting fully loaded pallets. The objective of this laboratory study was to quantify muscle activity, posture, and low back compressive and shear forces while completing typical pallet jack activities using a standard handle that required one handed pulling of a pallet jack compared to an alternative handle that allowed for two handed pushing. MethodsParticipants (n = 14) performed six to ten trials of common pallet jack tasks (straight travel and turning) with each handle. Posture analysis of the trunk and right upper extremity was performed using Motion Analysis (Santa Rosa, CA, USA) and back compressive and shear forces were analyzed using 3D Static Strength Prediction Program (University of Michigan, Ann Arbor, MI). Activity of the upper trapezius (UT), pectoralis major (PM), flexor digitorum superficialis (FDS) and extensor digitorum (ED) muscles were recorded (Telemyo 2400 T, Noraxon, Scottsdale, Arizona) and normalized to percent reference voluntary contraction values. All outcomes were compared using the paired t-test. ResultsPeak and mean muscle activity of the PM (p < 0.001) and ED (p < 0.01) were significantly higher using the alternative push handle during all three tasks. There were larger compressive forces at L4/L5 (p < 0.08) and L5/S1 (p < 0.002) using the alternative handle, and greater shear forces using the standard handle at both L4/L5 (p < 0.0001) and L5/S1 (p < 0.000). DiscussionThe standard handle outperformed the alternative handle with regard to muscle activity. The alternative handle had significantly greater compressive forces at L5/S1 due to the pushing nature of the hand-handle interface, yet the standard handle increased shear forces at both L4/L5 and L5/S1 levels in the low back. ConclusionIn this analysis, there was not a clear benefit to using either handle in terms of trunk strength capacity and varied benefits and drawbacks to each handle when comparing compressive and shear forces in the low back. However, given favorable subjective reports described in a prior publication, and the increased reliance on dynamic versus passive force production, facilitating a workers' ability to push a pallet jack while travelling with large loads is worth further investigation.

Simulation Experiment on Travelling Path Control of Differential Wheeled Pipeline Robot

For the travelling path control problem of differential wheeled pipeline robot, this paper proposes an approach to measure the velocities of drive wheels by photoelectric encoder, and gets trajectory curves of drive wheels on the experimental platform. Based on simulation of trajectory curves, fuzzy PID control of pipeline robot is fulfilled in straight travelling process. After PID parameters are implemented on the experimental robot fine control effectiveness is achieved.

Change point analysis of travel routes reveals novel insights into foraging strategies and cognitive maps of wild baboons

Efficient space use is a critical challenge for animals relying on stationary resources. It is often difficult with purely observational methods to gain unambiguous insight into any ability of primates to manage and process spatial information. Investigating the visible signs of the decision processes underlying space use often leaves open important issues. We applied the change point test [Byrne et al. (2009). Anim Behav 77: 619-631], a statistical tool to objectively determine change points (CPs) in animal travel paths, to investigate to what degree directional changes in our study group's (Papio ursinus) dry season ranging were associated with important resources and prominent landmarks. One-third of directional changes were associated with fruit feeding, 1/3 with traveling, and 1/3 with dry matter feeding, travel feeding and with drinking. When directional changes were associated with traveling, the subsequent directional changes were likely to result in fruit feeding. Fruit feeding mostly occurred at the apex of the day journeys, while drinking, dry matter feeding, and travel feeding often occurred along straight travel segments. The majority of directional changes did not occur in clusters at distinctive locations, but at distances of more than 120 m apart from each other, many of them along prominent landmarks. We conclude that the CPs do not represent nodes or route bends of a network map. Rather, they represent (1) locations where the decision to turn back to their sleeping site was taken, and (2) locations next to important landmarks (changes of slope, car tracks) where slight adjustment of a movement direction was possible. We found no evidence for a Euclidean map and discuss our findings in the light of a network map representation of space.

Research on Deviation Correction Control Technique of the Paver’s Traveling System

In order to improve the performance of crawler paver’s traveling and reduce the paver’s straight traveling deviation, a new control plan of paver’s traveling system was proposed. In the control plan, the left wheel control method adopted velocity closed loop control in order to keep constant-speed moving of the paver. The right wheel control method adopted the series structure of fuzzy control and PID control in which the fuzzy controller slightly adjusted the right wheel set point of PID controller according to the distance difference variable and velocity difference variable of paver’s left wheel and right wheel. In the working condition of straight paving, the real time deviation correction is achieved to assure paver’s straight traveling.

Importance of binocular vision in foot placement accuracy when stepping onto a floor-based target during gait initiation

This study investigated the importance of binocular vision to foot placement accuracy when stepping onto a floor-based target during gait initiation. Starting from stationary, participants placed alternate feet onto targets sequentially positioned along a straight travel path with the added constraint that the initial target (target 1) could move in the medio-lateral (M-L) direction. Repeated trials when target 1 remained stationary or moved laterally at the instant of lead-limb toe-off (TO) or 200ms after TO (early swing) were undertaken under binocular and monocular viewing. Catch trials when target 1 shifted medially were also undertaken. Foot-reach kinematics, foot trajectory corrections and foot placement accuracy for the step onto target 1 were determined via 3D motion analyses. Peak foot-reach velocity and initial foot-reach duration were unaffected by vision condition but terminal foot-reach duration was prolonged under monocular conditions (p=0.002). Foot trajectory alteration onsets were unaffected by vision condition, but onsets occurred sooner when the target shifted in early swing compared to at TO (p=0.033). M-L foot placement accuracy decreased (p=0.025) and variability increased (p=0.05) under monocular conditions, particularly when stepping onto the moving target. There was no difference between vision conditions in A-P foot placement accuracy. Results indicate that monocular vision provides sufficient information to determine stepping distance and correctly transport the foot towards the target but binocular vision is required to attain a precise M-L foot placement; particularly so when stepping onto a moving target. These findings are in agreement with those found in the reaching and grasping literature, indicating that binocular vision is important for end-point precision.

Gibbon travel paths are goal oriented

Remembering locations of food resources is critical for animal survival. Gibbons are territorial primates which regularly travel through small and stable home ranges in search of preferred, limited and patchily distributed resources (primarily ripe fruit). They are predicted to profit from an ability to memorize the spatial characteristics of their home range and may increase their foraging efficiency by using a 'cognitive map' either with Euclidean or with topological properties. We collected ranging and feeding data from 11 gibbon groups (Hylobates lar) to test their navigation skills and to better understand gibbons' 'spatial intelligence'. We calculated the locations at which significant travel direction changes occurred using the change-point direction test and found that these locations primarily coincided with preferred fruit sources. Within the limits of biologically realistic visibility distances observed, gibbon travel paths were more efficient in detecting known preferred food sources than a heuristic travel model based on straight travel paths in random directions. Because consecutive travel change-points were far from the gibbons' sight, planned movement between preferred food sources was the most parsimonious explanation for the observed travel patterns. Gibbon travel appears to connect preferred food sources as expected under the assumption of a good mental representation of the most relevant sources in a large-scale space.

An autonomous rice transplanter guided by global positioning system and inertial measurement unit

AbstractThis paper reports the development of an automated rice transplanter guided by a global positioning system and an inertia measurement unit using the controller area network bus. The actuator control command and data communication protocols comply with the ISO 11783. The project aims to develop an autonomous agricultural system for operation in the paddy field. The automated rice transplanter presented in this paper is the first stage in achieving the project objective. This paper focuses on the development of sensor and main computer connections to the operating autonomous unit and the use of common control protocols for each of the automated machines. A simple steering control algorithm was used for straight traveling. The automated rice transplanter made a turn at the headland of the paddy field and moved to the next desired path. After 12 straight operations, the rms lateral deviation was observed to be less than 0.04 m and the rms heading angle error was less than 3.6 deg. © 2009 Wiley Periodicals, Inc.

Radon Emanation Phenomena: A Probabilistic Basis to Estimate Radon Emanation Coefficients Based on Its Zigzag Travel

Previous theoretical approaches based on mathematical models by other researchers to the subject of radon emanation assumed straight linear travel of radon generated in grains constituting rocks or soils. However, it is difficult for these approaches to explain high radon emanation coefficients for rocks or soils without the introduction of the ideas of radon indirect recoil or a threshold for imbedding into grains. Unlike them, the present authors proposed anotherhypothesis based on the idea of radon zigzag travel and elucidated high radon emanation in a previous paper. The radon zigzag travel is caused by many collisions of radon with atoms constituting the grains. The results of the theoretical calculation successfully supported the claims of nanopore presence by Rama and Moore and radium layer presence near grain surfaces by Krishnaswami and Seidemann in a unified manner. However, the present authors think there is still room to improve their theory and they want to entice researchers toward a better explanation of high radon emanation for rocks or soils. Therefore, they give a probabilistic basis for their hypothesis and make a comparison between radon emanation coefficients obtained on straight linear and zigzag travel models, before concluding with a validity check of the models.

Age-related modifications in steering behaviour: effects of base-of-support constraints at the turn point

This study investigated the effects of altering the base of support (BOS) at the turn point on anticipatory locomotor adjustments during voluntary changes in travel direction in healthy young and older adults. Participants were required to walk at their preferred pace along a 3-m straight travel path and continue to walk straight ahead or turn 40 degrees to the left or right for an additional 2-m. The starting foot and occasionally the gait starting point were adjusted so that participants had to execute the turn using a cross-over step with a narrow BOS or a lead-out step with a wide BOS. Spatial and temporal gait variables, magnitudes of angular segmental movement, and timing and sequencing of body segment reorientation were similar despite executing the turn with a narrow or wide BOS. A narrow BOS during turning generated an increased step width in the step prior to the turn for both young and older adults. Age-related changes when turning included reduced step velocity and step length for older compared to young adults. Age-related changes in the timing and sequencing of body segment reorientation prior to the turn point were also observed. A reduction in walking speed and an increase in step width just prior to the turn, combined with a delay in motion of the center of mass suggests that older adults used a more cautious combined foot placement and hip strategy to execute changes in travel direction compared to young adults. The results of this study provide insight into mobility constraints during a common locomotor task in older adults.

Distance Between Random Points in Two Rectangular Cities

ABSTRACT The travel distance between two cities of rectangular shape is considered. Two uniformly distributed random points, one from each city, are taken. Their straight path travel distance is then measured. The explicit forms for the probability density function of this distance and its expected value are obtained. Numerical results of calculating the exact expected distance and the estimated distance as well as computer simulation are given for various cases. The integer moments of the distance are also discussed.

Dynamic Behavior of Rubber Tire-Mounted Gantry Cranes. 4th Report. Affection of Disturbance on Straight Travelling Performance.

Rubber Tire-mounted Gantry (RTG) crances are running on the runways, which are sloped in the transverse direction and waved caused by the bearing of the frequent heavy tire loads. RTG structure has a wide projection area against wind during travelling. The runway unevenness and wind load becomes a disturbance to divert the straight travelling trajectory. And the angular offset of tire supporting plane to the RTG body also becomes a significant factor to affect the straight travelling performance. Herein this paper, the modeling of runway surface and wind load are introduced, and the relation of straight travelling trajectory of RTG with affections of runway unevenness, wind load, and angular offset of tire are studied by analysis with FEM.

Dynamic Behavior of Rubber Tire-mounted Gantry Cranes. 2nd Report. Body Behavior and Travelling Performances.

Rubber Tire-mounted Gantry crane (RTG) is designed in a big gantry structure, and features some degree of flexibility and high position of its center of gravity. This results in a large influence against the travelling performaoces. The main factors affecting on the crane behavior (pitching romng and yawing) are the torque variation of the gantry-travel motors due to the road roughnes and inclination and the dynamic interactive forces between the tires and runway surface during the travelling motion. Based on both the experiments by actual RTG and simulation analysis, this paper clarifies the influence of the crane behavior on the travelling traiectory during straight travelling.

Dynamic Behavior of Rubber Tire-mounted Gantry Cranes. 3rd Report. Power-Line Characteristics and Straight Travelling Performances.

Rubber Tire-mounted Gantry (RTG) cranes are not equipped with the mechanical steering device, but steered by means of the differential rotational velocity of the driving wheels on right and left sides. Accordingly, the power line design is the most important for the optimization of RTG's travelling performance. Herein this paper, the characteristics of the driving motors and tires, and the dynamic analysis with FEM in travelling are described. The effects of them over the straight travelling perfomance are discussed. As for the tire characteristics, the effectiveness of rolling resistance, friction coefficient, cornering stiffness and rolling radius are proved to be mostly concerned to the straigh ttravelling performance. The four corners drive system is proved to improve the straight-travelling better compared to the two opposite corners driven system.

Dynamic Behavior of Rubber Tire-Mounted Gantry Cranes. 1st Report. Traveling Simulation.

This paper describes a modeling method for simulating the traveling characteristics of Rubber Tire-mounted Gantry (RTG) cranes. The modeling methods of the gantry frame, tires, and driving motors are introduced, since these are the primary factors affecting the crane traveling performance. The dynamic simulation is based on the Finite Element Method. Simulation cases for different trolley positions and gantry traveling speeds are developed and compared with experimental results. The effectiveness of this simulation method is proven by the strong correlation between the simulation and experimental results. The effective factors on RTG traveling performance (straight traveling and turning) are discussed regarding the RTG's structural characteristics.

5472341 Burner having low pollutant emissions

Transportation of materials using a pallet jack pulled behind the operator is common due to the visual advantages while transporting fully loaded pallets. The objective of this laboratory study was to quantify muscle activity, posture, and low back compressive and shear forces while completing typical pallet jack activities using a standard handle that required one handed pulling of a pallet jack compared to an alternative handle that allowed for two handed pushing.Participants (n = 14) performed six to ten trials of common pallet jack tasks (straight travel and turning) with each handle. Posture analysis of the trunk and right upper extremity was performed using Motion Analysis (Santa Rosa, CA, USA) and back compressive and shear forces were analyzed using 3D Static Strength Prediction Program (University of Michigan, Ann Arbor, MI). Activity of the upper trapezius (UT), pectoralis major (PM), flexor digitorum superficialis (FDS) and extensor digitorum (ED) muscles were recorded (Telemyo 2400 T, Noraxon, Scottsdale, Arizona) and normalized to percent reference voluntary contraction values. All outcomes were compared using the paired t-test.Peak and mean muscle activity of the PM (p < 0.001) and ED (p < 0.01) were significantly higher using the alternative push handle during all three tasks. There were larger compressive forces at L4/L5 (p < 0.08) and L5/S1 (p < 0.002) using the alternative handle, and greater shear forces using the standard handle at both L4/L5 (p < 0.0001) and L5/S1 (p < 0.000).The standard handle outperformed the alternative handle with regard to muscle activity. The alternative handle had significantly greater compressive forces at L5/S1 due to the pushing nature of the hand-handle interface, yet the standard handle increased shear forces at both L4/L5 and L5/S1 levels in the low back.In this analysis, there was not a clear benefit to using either handle in terms of trunk strength capacity and varied benefits and drawbacks to each handle when comparing compressive and shear forces in the low back. However, given favorable subjective reports described in a prior publication, and the increased reliance on dynamic versus passive force production, facilitating a workers' ability to push a pallet jack while travelling with large loads is worth further investigation.

Systematic errors arising from the application of mean input data in long-term air pollution transport models

The effect of applying mean (i.e. temporally and spatially averaged) input data (removal coefficients, wind velocity, travel distance between source and receptor) in a long-term model of the transport of heavy metals (especially As) in Europe's atmosphere has been investigated by running modified versions of this model. At five receptors considered in this study, the application of mean removal coefficients in the model resulted in an underprediction of concentration values and dry deposition, being approximately 0.75 times the original values, and an overestimation of wet deposition by a factor of approximately 1.5. The assumption of straight travel of pollutants between a source and some receptor brings about an overestimation of concentration and deposition by a factor of approximately 1.2. The application of mean wind velocity changed results only slightly. All occurring effects have also been investigated theoretically, so that assertions and formulae which are independent of the special model under consideration have been obtained.