A Novel Precision Measuring Parallel Mechanism for the Closed-Loop Control of a Biologically Inspired Lower Limb Exoskeleton

This paper introduces a multiposture locomotor training device (MPLTD) with a closed-loop control scheme based on joint angle feedback, which is able to overcome various difficulties resulting from mechanical vibration and the weight of trainer to achieve higher accuracy trajectory. By introducing the force-field control scheme used in the closed-loop control, the device can obtain the active-constrained mode including the passive one. The MPLTD is mainly composed of three systems: posture adjusting and weight support system, lower limb exoskeleton system, and control system, of which the lower limb exoskeleton system mainly includes the indifferent equilibrium mechanism with two degrees of freedom (DOF) and the driving torque is calculated by the Lagrangian function. In addition, a series of experiments, the weight support and the trajectory accuracy experiment, demonstrate a good performance of mechanical structure and the closed-loop control.

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Structure Design and Closed-Loop Control of a Modular Soft-Rigid Pneumatic Lower Limb Exoskeleton

Mechatronics and Machine Vision in Practice 4 ◽

10.1007/978-3-030-43703-9_17 ◽

2020 ◽

pp. 207-214

Author(s):

Jiangbei Wang ◽

Yanqiong Fei

Keyword(s):

Lower Limb ◽

Closed Loop ◽

Structure Design ◽

Closed Loop Control ◽

Loop Control ◽

Lower Limb Exoskeleton

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System Design and Study on Bionic Eye of Spherical Parallel Mechanism Based on Attitude Closed-loop Control

ROBOT ◽

10.3724/sp.j.1218.2011.00354 ◽

2011 ◽

Vol 33 (3) ◽

pp. 354-359 ◽

Cited By ~ 3

Author(s):

Chao LI ◽

Shaorong XIE ◽

Hengyu LI ◽

Jinsong MIAO ◽

Yuanyu XU ◽

...

Keyword(s):

System Design ◽

Parallel Mechanism ◽

Closed Loop ◽

Closed Loop Control ◽

Loop Control ◽

Bionic Eye ◽

Spherical Parallel Mechanism

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A novel 5-DOF high-precision compliant parallel mechanism for large-aperture grating tiling

Mechanical Sciences ◽

10.5194/ms-8-349-2017 ◽

2017 ◽

Vol 8 (2) ◽

pp. 349-358 ◽

Cited By ~ 6

Author(s):

Zhongxi Shao ◽

Shilei Wu ◽

Jinguo Wu ◽

Hongya Fu

Keyword(s):

High Precision ◽

Parallel Mechanism ◽

Closed Loop ◽

Load Capacity ◽

Performance Testing ◽

Closed Loop Control ◽

Parallel Mechanisms ◽

Loop Control ◽

Large Aperture ◽

Compliant Parallel Mechanism

Abstract. In combination with the advantages of parallel mechanisms and compliant mechanisms, a 5-DOF compliant parallel mechanism is designed to meet the requirements, such as large stroke, large load capacity, high precision and high stability, for a large-aperture grating tiling device. The structure and characteristics of the 5-DOF compliant parallel mechanism are presented. The kinematics of the mechanism are derived based on a pseudo-rigid-body model as well. To increase the tiling position retention stability of the mechanism, a closed-loop control system with capacitive position sensors, which are employed to provide feedback signals, is realized. A position and orientation monitoring algorithm and a single neuron adaptive full closed-loop control algorithm are proposed. Performance testing is implemented to verify the accuracy and the tiling position retention stability of the grating tiling device. The experimental results indicate that the tiling accuracy reaches 0.2 µrad per step and 20 nm per step, and the tiling position retention stability can achieve 1.2 µrad per 30 min and 35 nm per 30 min in the rotational direction and the translational direction, respectively.

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The Impact of Visual Feedback Type on the Mastery of Visuo-Motor Transformations

Zeitschrift für Psychologie ◽

10.1027/2151-2604/a000084 ◽

2012 ◽

Vol 220 (1) ◽

pp. 3-9 ◽

Cited By ~ 4

Author(s):

Sandra Sülzenbrück

Keyword(s):

Empirical Research ◽

Visual Feedback ◽

Closed Loop ◽

Motor Planning ◽

Visual Input ◽

Closed Loop Control ◽

Loop Control ◽

Feedback Type ◽

Effective Use ◽

The Impact

For the effective use of modern tools, the inherent visuo-motor transformation needs to be mastered. The successful adjustment to and learning of these transformations crucially depends on practice conditions, particularly on the type of visual feedback during practice. Here, a review about empirical research exploring the influence of continuous and terminal visual feedback during practice on the mastery of visuo-motor transformations is provided. Two studies investigating the impact of the type of visual feedback on either direction-dependent visuo-motor gains or the complex visuo-motor transformation of a virtual two-sided lever are presented in more detail. The findings of these studies indicate that the continuous availability of visual feedback supports performance when closed-loop control is possible, but impairs performance when visual input is no longer available. Different approaches to explain these performance differences due to the type of visual feedback during practice are considered. For example, these differences could reflect a process of re-optimization of motor planning in a novel environment or represent effects of the specificity of practice. Furthermore, differences in the allocation of attention during movements with terminal and continuous visual feedback could account for the observed differences.

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