Moving the Goal Posts in movement pattern modification using a robotic force field

Background Moving the Goal Posts (MGP) typically refers to a progressive change of goal or objective - a classic mechanism to promote motor function improvement in neuro-rehabilitative therapy. However, this MGP idea is still missing in the literature of robotic-assisted strategies to improve quality of movement, which is of high-importance in motor neuro-rehabilitation. This study aims to investigate if an MGP approach in a robotic-assisted upper limb movement pattern modification leads to a larger swivel angle change on healthy subjects during a reaching task training. Methodology Randomised control single blind study. Healthy naive subjects were allocated into two groups: Control (N=10) and MGP (N=10) and performed the same reaching tasks under different interventions provided by a manipulandum robotic device. During the intervention, the robotic device applied an Indirect Shaping Control (ISC): a resistive viscous force applied at the subject's hand as a function of the subject's swivel angle to encourage a modification of the later towards a 10° increase. In the MGP group, the goal was altered progressively towards the overall 10° increase in swivel angle, while in the Control group, the goal was set constant to the 10° from the beginning. Results A significant increase of the swivel angle, of 4.0° and 6.2° respectively, was observed in both groups (p<0.05). A significantly larger change was observed in the MGP group (p<0.001). All but one subject adapted into a new movement pattern, but no significant retention was observed in any of the two groups after intervention. Conclusion The superior effect of the intervention with the MGP approach compared to the constant goal demonstrates that the progressivity of learning plays an important role in this context and can ultimately lead to larger changes. Nevertheless, in both cases the effect of the intervention was small and longer interventions and/or steeper progressivity should be investigated to obtain larger changes. Retention was not observed in any group, but this may be different in a motor neuro-rehabilitation context where the newly taught movement pattern may result in additional movement capabilities or other benefits for neurologically impaired individuals.

PENGARUH TWIST ANGLE BLADE TURBIN SAVONIUS BERPENGARAH ALIRAN APLIKASI PADA TURBIN AIR

Water turbine is one of the mechanical equipment that functions to generateenergy into mechanical energy. There are types of water turbines one of which isthe Savonius water turbine. Savonius water turbines have the advantage of otherturbines, namely installation in rivers that do not damage the environment, areable to work and do not require special maintenance as well as providingweaknesses that can affect the positive force and the negative force on the rotor isstill small. This turbine has never been widespread. To make this turbine it ispossible to conduct research to improve its performance, especially in the turbinerotor. In these words we will try the rattan turbine by varying the blade's turningangle from 00, 30o, 60o, 90o and 120o and adding ½ and ¼ opening flow guides.Based on the results of the research that we have done, we can say the differencein blade angle and flow guide to turbine performance. The variation of twist angleand flow controller that provides the most appropriate turbine performance is a90o swivel with turbine flow guide openings ¼. At the swivel angle 120o the waveguide is not as wide.

Online human-like redundancy optimization for tele-operated anthropomorphic manipulators

Robot human-like behavior can enhance the performance of human–robot cooperation with prominently improved natural interaction. This also holds for redundant robots with an anthropomorphic kinematics. In this article, we translated human ability of managing redundancy to control a seven degrees of freedom anthropomorphic robot arm (LWR4+, KUKA, Germany) during tele-operated tasks. We implemented a nonlinear regression method—based on neural networks—between the human arm elbow swivel angle and the hand target pose to achieve an anthropomorphic arm posture during tele-operation tasks. The method was assessed in simulation and experiments were performed with virtual reality tracking tasks in a lab environment. The results showed that the robot achieves a human-like arm posture during tele-operation, and the subjects prefer to work with the biologically inspired robot. The proposed method can be applied in control of anthropomorphic robot manipulators for tele-operated collaborative tasks, such as in factories or in operating rooms.

Analytical Inverse Kinematic Resolution of a Redundant Exoskeleton for Upper-Limb Rehabilitation

Robot-assisted therapy has played a significant role in helping the disabled patients to restore motor functions. In this paper, a redundant exoskeleton is developed for upper-limb rehabilitation. An analytical methodology for obtaining the inverse kinematic solution of the exoskeleton is presented to provide synchronized movement with patients and ensure natural human–robot interaction. To mathematically express the redundancy problem, the swivel angle of elbow is introduced as an additional parameter to specify the human arm congratulation with a predefined wrist location. A kinematic criterion is proposed to determine the swivel angle by imitating the natural reflexive reaction of human arm. The effectiveness of the proposed strategy is experimentally evaluated via four representative types of upper-limb motion tasks. During the experiments, the actual kinematic data of human arm is collected by utilizing an articulated motion capture system integrated with inertial sensors and, after that, compared to the estimation results generated by the proposed redundancy resolution. The experimental results indicate that the kinematic criterion of swivel angle is suitable to describe the free reaching movement without additional constraints. Moreover, with the estimated swivel angles, the root mean square errors between the actual and calculated joint angles are normally less than 8[Formula: see text].

Lead Crowning and Anti-Twist for Tooth Flank of a Heat Treated Helical Gear on Internal CNC Honing Machine

The internal gear honing is more popular than the external gear honing by its advantages such as higher contact surface and easier correct profile errors. It is usually applied for modifying the gear surface to compensate for the distortions after heat treatment process. However, the lead crowning and anti-twist tooth flank of a helical gear on internal CNC gear honing has not studied yet. Therefore, a novel method for lead crowning tooth flank of work gear surfaces is proposed by using a linear swivel angle function of the honing wheel and a variable pressure angle (VPA) honing wheel is also applied for anti-twist of the crowned tooth flank in honing process.

Analysis of Roughness in Super-High Speed Point Grinding

The technology of super-high speed point (SHSP) grinding will bring in higher precision and productivity for component manufacturing. The surface roughness attained by SHSP grinding is analyzed in this paper based on the contact area and the probability distribution of chip thickness while the swivel angle of α exists, proposing a new method to predicate the value of the roughness, the experiment of SHSP grinding is carried out whether α exists or not to verify the theoretical analysis in the paper, through observing the micro-surface after grinding, the conclusions will be drawn at last.

Analysis of Super-High Speed Point Grinding Forces

Super high-speed point grinding is a good performance grinding with high surface quality due to its low force. To model point grinding forces including swivel angle formed by tilting wheel to the horizontal workpiece axis seems necessary. In this research, a point grinding force model was present, and the point grinding forces are influenced by factors such as grinding depth, wheel velocity, swivel angle as well as equivalent diameter. And then some experimental tests are carried out. It is found that the experimental data was in good agreement with theoretical model.