Analytic Formulation of Reciprocal Screws and Its Application to Nonredundant Robot Manipulators

As the kinematics and statics play a very important role in determining the actuating inputs and the effective loads that the end-effector sustains, this article focuses on this issue and proposes an analytical process to study the forward and inverse kinematics and statics of spatial manipulators. As series manipulators and parallel manipulators show different features in kinematics and statics, this article discusses them separately. First, the forward and inverse velocity problems of the manipulator linkages are investigated with reciprocal screw theory. Then, the static balance conditions together with forward and inverse statics of the manipulator linkages are established through virtual power theory. In the kinematics analysis, the primary conditions for feasible motions of an end-effector are addressed through velocity screws. Illustrative examples indicate that the method proposed in this article can be used to guide the singularity identification, path planning, and feasible motion determination.

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“…Thus, the basic solution systems (8) and (9) are equivalent. So there must be 7 − n = 6 − n, which is obviously wrong.…”

Section: Velocity Analysis Of Series Manipulatorsmentioning

confidence: 94%

The kinematics and statics of manipulators

Zhao

Chu

et al. 2009

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…Here, static ($ 0 ) and instantaneous kinematic ($) components are rectified concurrently and linked by the principle of reciprocity. In the field of robotic research, the screw system and the reciprocity relationships are valuable tools describing multi-degree-of-freedom motions (Kim and Chung 2003). In the following descriptive analysis, a reciprocal system of screws is characterised by five physical constraints within a knee joint, and is mechanically equivalent to one degree of freedom.…”

Section: Introductionmentioning

confidence: 99%

A reciprocal connection factor for assessing knee-joint function

Kim¹,

Kohles²

2012

Computer Methods in Biomechanics and Biomedical Engineering

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In the knee joint, interactions between instantaneous kinetics and kinematics associated with ligamentous and articular tissues are not fully understood. These structures may be represented by the instantaneous screw axis ($) (ISA) and static force vectors ($'). Geometric changes to the joint structure affecting motion have not been fully explained, especially after surgical reconstruction and replacement procedures. The ISA offers a joint-characterisation approach, which is dependent on the combined forces of ligaments, articular contacts and muscles. The standard four-bar linkage model in the sagittal plane demonstrates that the normal contact force and the lines of action of the cruciate ligaments always intersect at the centre of rotation of the joint. A kinematic knee model in which the articular surfaces in the lateral and medial compartments as well as the isometric fascicles in the engaged ligaments may be represented as five constraints in a one-degree-of-freedom parallel spatial mechanism. This study provides a theoretical foundation to elucidate the role of each of these elements in the control of the ISA. A recourse to the principle of virtual work explained through d'Alembert's principle for reducing a dynamics problem to an instantaneous static scenario allows screws to be applied to the biomechanics of human motion. The principle of reciprocity links these approaches together to explain the transmitting load between the tibia and the femur as well as the relative motion within the knee joint. A principal clinical implication of this study is the introduction of the reciprocal connection factor to evaluate knee kinematics and kinetics in one simple term, allowing the quantitative assessment of the outcome of knee-joint treatment and rehabilitation methods.

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“…Many applications demand manipulators with high degrees of repeatability, precision, and reliability. Therefore, some researches on the mechanical manipulator and its control have been done by many scholars [3][4][5]. In this paper, our designed the hydraulic-driven machine tool manipulator combined with CNC machine (machining centers, CNC milling machine, etc.)…”

Section: Introductionmentioning

confidence: 99%

Structural Design and PLC Control of the Machine Tool Manipulator

Wang¹

2012

Proceedings of the 2nd International Conference on Electronic and Mechanical Engineering and Information Technology (2012)

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Abstract.A kind of hydraulic-driven manipulator for machine tool is presented in this paper. Firstly, the manipulator's structure is designed and 3D model is built by using solidworks software. Secondly, the hydraulic system diagram for implementing the manipulator's sequences is established. Finally, control system of the machine tool manipulator is implemented based on PLC, and the experimental results show the correctness and feasibility of our design and control programs. Therefore, this can provide a certain referencing value for the practical production application. IntroductionThe industrial manipulator is a kind of automatic equipment, which can simulate the hand gestures of human been and achieve the automatic motion of grabbing, carrying and manipulation, according to the preset sequences, tracks and demands [1]. It is one of the most important equipments, which can realize the industrial production mechanization and automation [1,2]. Many applications demand manipulators with high degrees of repeatability, precision, and reliability. Therefore, some researches on the mechanical manipulator and its control have been done by many scholars [3][4][5]. In this paper, our designed the hydraulic-driven machine tool manipulator combined with CNC machine (machining centers, CNC milling machine, etc.) can form an automated production line to achieve processing (feeding, processing and automation of the cutting) without human interference.

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Analytic Formulation of Reciprocal Screws and Its Application to Nonredundant Robot Manipulators

Cited by 37 publications

References 10 publications

The kinematics and statics of manipulators

The kinematics and statics of manipulators

A reciprocal connection factor for assessing knee-joint function

Structural Design and PLC Control of the Machine Tool Manipulator

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