Motion Control Module Research Articles

Role of catecholamine signaling in brain and nervous system functions: new insights from mouse molecular genetic study.

Catecholamines, including dopamine and norepinephrine, are the principal neurotransmitters that mediate a variety of the central nervous system functions, such as motor control, cognition, emotion, memory processing, and endocrine modulation. Dysfunctions in catecholamine neurotransmission are implicated in some neurologic and neuropsychiatric disorders. Recent mouse molecular genetic approaches provide genetic evidence for an important role of catecholamines in brain functions. In this paper, I describe the phenotype of mutant mice with impairments in dopamine or norepinephrine biosynthesis. Mice defective in dopamine biosynthesis exhibit severe motor dysfunctions characterized by a reduction in spontaneous locomotion and cataleptic behavior, and defects in drug-induced hyperactivity at the juvenile stage. They also exhibit defects in the acquisition of conditioned learning dependent on tone stimulus. These results indicate that dopamine is essential for motor control and emotional learning during postnatal development, possibly through nigrostriatal and mesolimbic neuronal pathways. On the other hand, mice carrying the mutation in the gene encoding tyrosine hydroxylase (the rate-limiting enzyme of catecholamine biosynthesis) display a reduction in norepinephrine biosynthesis. This leads to deficits in latent learning and long-term memory formation of different conditioned learning paradigms. The results indicate that norepinephrine is essential for the consolidation process of long-term memory, suggesting that norepinephrine may control the neuronal activity in the cerebral cortex or amygdala to maintain the memory process of conditioned learning.

SAVI: an actively controlled teleconferencing system

A Stereo Active Vision Interface (SAVI) is introduced which detects frontal faces in real world environments and performs particular active control tasks dependent on hand gestures given by the person the system attends to. The SAVI system is thought of as a smart user interface for teleconferencing, telemedicine, and distance learning applications. To reduce the search space in the visual scene the processing is started with the detection of connected skin colour regions applying a new radial scanline algorithm. Subsequently, in the most salient skin colour region facial features are searched for while the skin colour blob is actively kept in the centre of the visual field of the camera system. After a successful evaluation of the facial features the associated person is able to give control commands to the system. For this contribution only visual control commands are investigated but there is no limitation for voice or any other commands. These control commands can either effect the observing system itself or any other active or robotic system wired to the principle observing system via TCP/IP sockets. The system is designed as a perception-action-cycle (PAC), processing sensory data of different kinds and qualities. Both the vision module and the head motion control module work at frame rate on a PC platform. Hence, the system is able to react instantaneously to changing conditions in the visual scene.

Integral system for assisted mobility

This paper presents the results of a research work carried out in the Electronics Department of the University of Alcalá in the field of electronic systems for the guidance of wheelchairs for the disabled and/or the elderly. These electronic systems have been designed to meet a wide range of needs experienced by users of this type of wheelchair. One of their most important features is their modularity, thereby making them adaptable to the particular needs of each user according to the type and degree of handicap involved. The overall system includes a complete user–machine interface, motor control modules and safety and autonomous guidance systems. The project is called: “Sistema Integral de Ayuda a la Movilidad (SIAMO)” (integral system for assisted mobility).

A paradigm for controlling virtual humans in urban environment simulations

This paper presents a new architecture for simulating virtual humans in complex urban environments. The approach is based on the integration of six modules. Four key modules are used in order to manage environmental data, simulate human crowds, control interactions between virtual humans and objects, and generate tasks based on a rule-based behavioral model. The communication between these modules is made through a client/server system. Finally, all low-level virtual human actions are delegated to a single motion and behavioral control module. Our architecture combines various human and object simulation aspects, based on the coherent extraction and classification of information froma virtual city database. This architecture is discussed in this paper, together with a detailed case study example.

Animated agents for procedural training in virtual reality: Perception, cognition, and motor control

This paper describes Steve , an animated agent that helps students learn to perform physical , procedural tasks . The student and Steve cohabit a three - dimensional , simulated mock - up of the student's work environment . Steve can demonstrate how to perform tasks and can also monitor students while they practice tasks , providing assistance when needed . This paper describes Steve's architecture in detail , including perception , cognition , and motor control . The perception module monitors the state of the virtual world , maintains a coherent representation of it , and provides this information to the cognition and motor control modules . The cognition module interprets its perceptual input , chooses appropriate goals , constructs and executes plans to achieve those goals , and sends out motor commands . The motor control module implements these motor commands , controlling Steve's voice , locomotion , gaze , and gestures , allowing Steve to manipulate objects in the virtual world .

Modular CNC Design for Intelligent Machining, Part 2: Modular Integration of Sensor Based Milling Process Monitoring and Control Tasks

Modular integration of sensor based milling process monitoring and control functions to a proposed CNC system architecture is presented. Each sensor based process control algorithm resides in a dedicated processor in the AT bus with a modular software. The CNC system’s motion control module has been designed to accomodate rapid manipulation of feeds, cutting conditions and NC tool path which may be demanded by machining process control modules in real time. Modular integration of adaptive control of cutting forces, tool condition monitoring, chatter detection and suppression tasks are illustrated as examples. The process control and monitoring modules are serviced in the real-time multi-tasking environment within one millisecond time intervals without disturbing the position control system. The paper present constraints and guidelines in designing CNC systems which allow modular integration of user developed real time machining process control and monitoring applications.

An intelligent software system for a robotics assembly cell

The research discussed in this paper is directed towards the development of an intelligent software system using a knowledge base and artificial intelligence approach for a flexible robotics assembly cell, which can automatically generate and verify a robot-level program based on sensory data with a CAD-based user interface. The system can perform various assembly tasks for different products on a single station without the aid of jigs and fixtures to present the parts. The developed system consists of several modules and subsystems including; a CAD-based user interface, a sensory system, a knowledge based system, a task planner module, a motion control module, and cell device controllers. The system has two modes, a learning mode and an execution mode. The learning mode provides the facility to introduce component objects of each product to the system, and to automatically create a knowledge base for all the objects, which is based on both the data received from sensors in the workplace and from the CAD database. In the execution mode, the system can recognize any assembly part coming into the robot workspace, where recognition is based on selected component features, and can calculate the object's real position and orientation. Then, the motion planner modifies the object's assembly program, based on real position and orientation data. Finally, the system downloads motion commands via a robot interface into the robot controller, to perform the appropriate assembly operation.

Laminar compartmentalization of GABAA-receptor subtypes in the spinal cord: an immunohistochemical study

To assess the significance of GABAA-receptor heterogeneity, which is based on a family of at least 15 subunits, the cellular localization and subunit composition of GABAA-receptor subtypes were analyzed immunohistochemically in the rat spinal cord. The distribution of subunits alpha 1, alpha 2, alpha 3, alpha 5, beta 2,3, and gamma 2 was investigated with subunit-specific antibodies, and their colocalization within individual neurons was visualized by double-immunofluorescence staining. The results reveal a widespread expression of the subunits, alpha 3, beta 2,3, and gamma 2 in the spinal cord, whereas the three other alpha subunits displayed a more restricted, lamina-specific distribution. The alpha 1 and alpha 5 subunits were most abundant in the intermediate zone, whereas the alpha 2 subunit was predominant in the superficial layers of the dorsal horn and in somatic and preganglionic motoneurons. From colocalization studies, seven subunit combinations could be identified (alpha 3/beta 2,3/gamma 2; alpha 2/beta 2,3/gamma 2; alpha 1/beta 2,3/gamma 2; alpha 5/beta 2,3/gamma 2; alpha 1/alpha 5/beta 2,3/gamma 2; alpha 2/gamma 2; alpha 2/alpha 5/gamma 2) that correspond presumably to distinct receptor subtypes. Although most neurons expressed the subunit triplet alpha x/beta 2,3/gamma 2, the beta 2,3 subunits could not be detected in motoneurons that may thus possess "atypical" receptor subtypes (alpha 2/gamma 2 and alpha 2/alpha 5/gamma 2). ON the subcellular level, aggregates of immunoreactivity, suggestive of postsynaptic GABAA receptors, typically were seen on the surface of neuronal somata and proximal dendrites. In addition, an intense diffuse staining was observed in laminae I--III for the subunits alpha 2, alpha 3, beta 2,3, and gamma 2, presumably localized on primary afferent terminals. The localization of GABAA-receptor subtypes in distinct laminar compartments of the spinal cord suggests that GABAA-receptor heterogeneity is of relevance for the modulation of sensory inputs, nociception, and motor control at segmental levels.

Electronic control of a wheelchair guided by voice commands

This paper describes the control of an electric wheel chair with voice commands. This chair has been developed and built at the U.A.H. Electronic Department and financed by the ONCE Foundation (Spain). The first prototype consists of voice recognition, motor control, user interface and central processor modules. The electronic system allows the chair user a safe, easy ride, and guarantees the concordance between user commands and actual trajectories. Furthermore, the system has been designed to allow the addition of future features, like obstacle and stair detection and the tele-commanding of electrical household appliances from the chair.

Mesh-glove. 2. Modulation of residual upper limb motor control after stroke with whole-hand electric stimulation.

The effects of whole-hand electrical stimulation via a wired mesh-glove upon the residual motor control of the upper extremity are described. Clinical observations were made in 2 patients with nonfunctional upper limbs, 4 and 2 years after stroke, who had been enrolled in the home mesh-glove program for 6 and 4 months, respectively. The stimulation paradigm is novel and the target of stimulation is the hand. Preliminary results indicate beneficial effects such as reduction in muscle hypertonia and facilitation of isolated hand movements

Mesh-glove. 2. Modulation of residual upper limb motor control after stroke with whole-hand electric stimulation

The effects of whole-hand electrical stimulation via a wired mesh-glove upon the residual motor control of the upper extremity are described. Clinical observations were made in 2 patients with nonfunctional upper limbs, 4 and 2 years after stroke, who had been enrolled in the home mesh-glove program for 6 and 4 months, respectively. The stimulation paradigm is novel and the target of stimulation is the hand. Preliminary results indicate beneficial effects such as reduction in muscle hypertonia and facilitation of isolated hand movements.

接触状態変化検出機能を有するマニピュレーションシステムに関する検討

In a manipulation system that executes assembly tasks, contact-state recognition or contact-state-transition detection are important functions. These functions should be modularized as a motion monitoring and evaluation (MME) module. This paper mainly presents a real-time detection method of contact-state-transition with high reliability, and the implementation of the method into the MME module. In the detection algorithm, features which fluctuate abruptly when the contact-state-transition occur are selected according to the motion pattern. In the detection algorithm, the differential of the feature locus is monitored and the transition region is distinguished from the stable region. Then, to confirm whether state-transition really occur in the region, the duration of the region and the feature deviation are counted. Using this method, contact-state-transition is detected with only 40 [msec] delay. An experimental manipulation system, in which motion control and MME modules are independently executed, is developed using transputers and the 6 D.O.F direct drive manipulator ETA 3. In the experiment, six patterns of motion, in which different types of transition occur, are selected. The experimental results show that contact-state-transition is accurately detected and motion commands can be quickly switched using detected transition information.

Sinoaortic baroreceptor reflex arc modulation of nociception in spontaneously hypertensive and normotensive rats

Spontaneously hypertensive rats of the Okamoto-Aoki strain (SHR) and normotensive rats of the Wistar-Kyoto strain (WKY) were assessed in hot-plate and flinch-jump analgesimetric assays. SHRs manifested longer latencies than WKYs to both paw-lick and jump in response to painful thermal stimulation in the hot-plate assay, but SHRs had lower flinch and jump thresholds than WKYs to electric shock stimulation in the flinch-jump assay. Bilateral sinoaortic deafferentation did not alter response latencies of either SHRs or WKYs in the hotplate assay, but significantly lowered flinch and jump thresholds of both SHRs and WKYs in the flinch-jump assay. These findings are discussed in terms of baroreceptor reflex arc modulation of endogenous pain-regulatory systems and motor control.