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On rough terrain, excessive wheel slippage is easily generated by changes of surface conditions such as soil types and geometries. It induces considerable loss of wheel traction and battery energy. To prevent this, wheeled robots should consistently recognize the current situation generated between wheel and surface. And also wheeled robots are required to optimally control wheel motion in limited wheel traction and battery capacity. Therefore, this paper proposes a novel wheel control algorithm based on slip optimization of traction and energy, which is adaptive to change of surface condition. Proposed wheel control algorithm is called Traction-Energy Balancing Adaptive Control (TEB) in this paper and TEB assigns optimized rotation speed to each wheel by observing wheel slip ratio which is a key parameter of TEB. As functions of TEB, TEB is largely divided into three main parts; (1) slip optimizer (2) slip controller (3) SC-compensator. In the slip optimizer, two optimal slip models were derived as a function of slip ratios regarding maximum traction and tractive efficiency using experimental data about wheel-terrain interaction in three types of soil (grass, gravel and sand). And the optimal slip models were employed in order to determine a desired slip value of wheel with observation of a change in actual robot velocity as control input in the slip controller. For optimal slip control, the proposed slip controller is based on conventional PID controller with compensating disturbance in the controller (SC-compensator) which occurs by change of surface shapes. In the SC-compensator, radial function networks (RBFN) was applied in the slip controller and RBFN was of help to readjust previously set PID gains depending on occurred slip error. Finally, TEB was experimentally verified by controlling a real robot having four wheels on various terrain types. 相似文献
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Background and objectives: Developmental theorists posit that temperament contributes to preadolescent’s stress response styles. Findings from empirical studies, however, have yielded mixed results, thus indicating a need to consider moderators of this relation. Utilizing an analytic framework guided by resiliency theory [Zimmerman, M. A. (2013). Resiliency theory: A strengths-based approach to research and practice for adolescent health. Health Education &; Behavior, 40, 381–383], this study examined achievement goal orientation as a moderator of the relation between temperament and stress response styles.Methods: 96 preadolescent–parent dyads (Mage?=?10.30 years, range?=?9–12 years) participated in the study. Preadolescents reported on their achievement goal orientation, coping and involuntary stress responses (ISRs) styles and a parent reported on children’s temperament.Results: Multiple regressions revealed that effortful control positively predicted preadolescent’s predominant use of engagement coping and negatively predicted predominance of ISRs, but only for children with a predominant mastery goal orientation. For preadolescents with a predominant performance goal orientation, effortful control negatively predicted the predominant use of engagement coping and positively predicted predominance of ISRs. Negative affectivity and its interaction with goal orientation did not predict coping or ISR styles.Conclusions: Findings suggest that a predominant mastery goal orientation may function as a promotive factor by enhancing the contribution of effortful control to engagement coping styles and buffering against unmanaged reactivity. 相似文献
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Background: Cognitive models propose that attentional biases to threat contribute to the maintenance of social anxiety disorder (SAD). However, the specific characteristics of such biases are still object to debate.Objectives: The current study aimed to disentangle effects of trait and state social anxiety on attention allocation towards social stimuli.Methods: Participants with SAD (n?=?67) and healthy controls (n?=?62) completed three visual search tasks while their eye movements were recorded. Half of the participants in each group were randomly assigned to a state anxiety induction.Results: Contrary to our predictions, neither trait nor state social anxiety was associated with a facilitated attention to or a delayed disengagement from threat. However, participants with SAD did show reduced fixation durations for threatening stimuli, indicating an avoidance of threat. Induction of state anxiety led to an increased distractibility by threat.Conclusions: We suggest that attention allocation in SAD is characterized by an avoidant rather than a vigilant attentional bias. Accordingly, our results contradict previous results that associate SAD with facilitated attention to threat and existing approaches to modify attentional biases, that aim to decrease attention towards threatening stimuli. 相似文献
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This study identified the level of trunk control of healthy term infants aged from six to nine months. This cross-sectional study included fifty-five infants aged from six to nine months. The levels of trunk control was investigated by using the Segmental Assessment Trunk Control (SATCo). The infants remained seated on a wooden bench and a neutral pelvic position was maintained. The SATCo score was considered as dependent variable. The results showed that infants aged six and seven months presented levels of trunk control in the thoracic region while infants aged from eight to nine months presented full trunk control. These results demonstrate that younger infants present less levels of trunk control while older infants present full trunk control, confirming that trunk control development takes place in a segmental way and in a cephalocaudal direction. These results also might be used as a reference to distinguish infants that show a delay in trunk control from those who have suitable motor development and, thus intervene at an early stage to minimize later delays in these infantś global motor development. 相似文献
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Calming an aggressor through spontaneous post‐conflict triadic contacts: Appeasement in Macaca tonkeana
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209.
The contribution of executive control to semantic cognition: Convergent evidence from semantic aphasia and executive dysfunction
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Hannah E. Thompson Azizah Almaghyuli Krist A. Noonan Ohr barak Matthew A. Lambon Ralph Elizabeth Jefferies 《Journal of Neuropsychology》2018,12(2):312-340
Semantic cognition, as described by the controlled semantic cognition (CSC) framework (Rogers et al., 2015 , Neuropsychologia, 76, 220), involves two key components: activation of coherent, generalizable concepts within a heteromodal ‘hub’ in combination with modality‐specific features (spokes), and a constraining mechanism that manipulates and gates this knowledge to generate time‐ and task‐appropriate behaviour. Executive–semantic goal representations, largely supported by executive regions such as frontal and parietal cortex, are thought to allow the generation of non‐dominant aspects of knowledge when these are appropriate for the task or context. Semantic aphasia (SA) patients have executive–semantic deficits, and these are correlated with general executive impairment. If the CSC proposal is correct, patients with executive impairment should not only exhibit impaired semantic cognition, but should also show characteristics that align with those observed in SA. This possibility remains largely untested, as patients selected on the basis that they show executive impairment (i.e., with ‘dysexecutive syndrome’) have not been extensively tested on tasks tapping semantic control and have not been previously compared with SA cases. We explored conceptual processing in 12 patients showing symptoms consistent with dysexecutive syndrome (DYS) and 24 SA patients, using a range of multimodal semantic assessments which manipulated control demands. Patients with executive impairments, despite not being selected to show semantic impairments, nevertheless showed parallel patterns to SA cases. They showed strong effects of distractor strength, cues and miscues, and probe–target distance, plus minimal effects of word frequency on comprehension (unlike semantic dementia patients with degradation of conceptual knowledge). This supports a component process account of semantic cognition in which retrieval is shaped by control processes, and confirms that deficits in SA patients reflect difficulty controlling semantic retrieval. 相似文献
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The aim of this study was to provide a detailed account of the spatial and temporal disruptions to eye-hand coordination when using a prosthetic hand during a sequential fine motor skill. Twenty-one able-bodied participants performed 15 trials of the picking up coins task derived from the Southampton Hand Assessment Procedure with their anatomic hand and with a prosthesis simulator while wearing eye-tracking equipment. Gaze behavior results revealed that when using the prosthesis, performance detriments were accompanied by significantly greater hand-focused gaze and a significantly longer time to disengage gaze from manipulations to plan upcoming movements. The study findings highlight key metrics that distinguish disruptions to eye-hand coordination that may have implications for the training of prosthesis use. 相似文献