Perfect Static Balance of Linkages by Addition of Springs But Not Auxiliary Bodies

Deepak, Sangamesh R.; Ananthasuresh, G. K.

doi:10.1115/1.4006521

Cited by 41 publications

(7 citation statements)

References 16 publications

(46 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Possible applications for this spring are in the macro scale, where joints can be made such as weight balancing [13,24], robotics [10,11] and arm support [7,8]. Especially for systems with low stiffness in transverse direction or rotation this would be a good spring, since there are no parasitic transverse forces or torques which could cause errors in the movement of the system.…”

Section: Figure 11mentioning

confidence: 99%

Design and optimization of a general planar zero free length spring

Delissen

Radaelli

Herder

2017

Mechanism and Machine Theory

View full text Add to dashboard Cite

Design and optimization of a general planar zero free length spring Delissen, Arnoud A.T.M.; Radaelli, Giuseppe; Herder, Just L. AbstractA zero free length (ZFL) spring is a spring with special properties, which is commonly used in static balancing. Existing methods to create ZFL springs all have their specific drawbacks, which rises to the need of a new method to create such a spring. A method is proposed to design planar ZFL springs with specified stiffness (250-750 N/m) within a certain range (up to 20 mm of displacement). Geometric non-linearities of a curved leaf spring are exploited by changing its shape. The shape is determined by a non-linear least squares algorithm, minimizing the force residuals from a non-linear numerical analysis. Constraints are introduced to help in preventing the spring from intersecting itself during deformation. For three types of springs with different boundary conditions, designs are found with characteristic shapes and maximum force errors less than 1%. A trend is observed between spring size, maximum stress and desired stiffness. New type of ZFL springs can now be designed, which can not only be used in existing applications, but also enables the use of ZFL springs in micro mechanisms. KeywordsZero free length spring; null-length spring; ideal spring; curved flexure; shape optimization; desired forcedisplacement List of variables (in order of appearance)Reaction/spring force Spring stiffness Displacement 0

show abstract

Section: Figure 11mentioning

confidence: 99%

Design and optimization of a general planar zero free length spring

Delissen

Radaelli

Herder

2017

Mechanism and Machine Theory

View full text Add to dashboard Cite

show abstract

“…For a serial planar manipulator with only revolute joints, the method to balance gravity with springs has been proposed by refs. [15][16][17][18], of which the springs are directly attached to the manipulator. Ref.…”

Section: Introductionmentioning

confidence: 99%

Spring-balanced 3-DoF serial planar manipulators for constant forces in arbitrary directions

2023

View full text Add to dashboard Cite

With the use of springs, a method to balance the constant forces in arbitrary directions on a planar serial manipulator is developed in this study. Gravity balancing has been discussed a lot in the past. However, manipulators usually bear forces from various directions rather than only a fixed one as gravity. For instance, an industrial manipulator would bear forces from everywhere during the working process. Therefore, a method to balance these forces in arbitrary directions with springs is proposed. Based on the representation of energy, spring energy is the function of springs’ attachment points. Two spring systems with different attachment angles are needed to balance respectively forces in arbitrary directions and gravity. The spring installations of the above systems on 3-DoF manipulators are proposed. Finally, a resistive force-balanced manipulator with/without gravity balance in the grinding process is shown. In sum, this paper for the first time develops the balancing method for forces in arbitrary directions, expanding the spring balance theory to a broader application.

show abstract

“…Also, the additional mass of additional devices may increase the load of springs. To mitigate these problems, balancing methods that do not use auxiliary links but directly attach the springs to the manipulator have been proposed (Lin et al, 2011;Deepak and Ananthasuresh, 2012;Lee and Chen, 2014;Juang and Chen, 2022) and used in this paper. The gravity balancing method without auxiliary links uses springs to balance the gravity of manipulators systematically.…”

Section: Introductionmentioning

confidence: 99%

“…This means that the springs are more efficiently used; hence, the system would be safer, and its service life would be extended. The gravity balancing method by springs without auxiliary links is developed (Lin et al, 2011;Deepak and Ananthasuresh, 2012;Lee and Chen, 2014; Juang and Chen, 2022), but there are no research papers discussing the issue of how to use springs efficiently to balance the gravity of a manipulator. This study aims to develop a method to use springs efficiently, and thereby, the assessment of the spring efficiency is presented here.…”

Section: Introductionmentioning

confidence: 99%

Spring efficiency assessment and efficient use of spring methods of statically balanced planar serial manipulators with revolute joints only

Juang

Jhuang²,

Chen³

2022

Mech. Sci.

View full text Add to dashboard Cite

Abstract. This paper proposes a spring efficiency assessment of a statically spring-balanced planar serial manipulator. The admissible spring configurations for the static balancing of planar serial manipulators without auxiliary links have been determined in the past. Gravity is balanced by the spring configuration systematically; however, the spring configuration also contains counter-effects between springs. Conceptually, with fewer counter-effects between springs, there is less burden on the spring system, which means that the springs are used more efficiently, and accordingly, the system would be safer, and its service life would be longer. In this study, the spring energy is represented in a quadratic form. The coefficients in a quadratic form represent the change in elastic energy with the relative position between links, which is named “elastic pseudo-stiffness”. Compared to the quadratic form of gravity energy, those elastic pseudo-stiffnesses for static balancing are regarded as positive contributions of a spring, while those that contain counter-effects are seen as negative ones. Spring efficiency is defined as the ratio of the elastic pseudo-stiffnesses, which has positive contributions for balancing to total elastic pseudo-stiffnesses. To use springs efficiently, the counter-effects, which are functions of spring parameters, need to be decreased, including spring stiffness and the attachment location of springs on links. A method to use spring efficiently by adjusting spring parameters is developed. Furthermore, it is found that, for a spring attached between adjacent links, the spring efficiency is 100 %, and the spring efficiency decreases while the number of joints over which the spring spans increases. In a spring manipulator system, the efficiency is negatively correlated to the payload. As an example, an efficiency assessment on a 3 degrees of freedom (DOF) manipulator is shown at the end.

show abstract

Perfect Static Balance of Linkages by Addition of Springs But Not Auxiliary Bodies

Cited by 41 publications

References 16 publications

Design and optimization of a general planar zero free length spring

Design and optimization of a general planar zero free length spring

Spring-balanced 3-DoF serial planar manipulators for constant forces in arbitrary directions

Spring efficiency assessment and efficient use of spring methods of statically balanced planar serial manipulators with revolute joints only

Contact Info

Product

Resources

About