Two-Point Floating Clamping Device Based on Fixed Cylinder with Double-Piston and Toggle-Lever Force Amplifier

2011 ◽  
Vol 201-203 ◽  
pp. 2220-2223 ◽  
Author(s):  
Guang Ju Si ◽  
Kang Min Zhong ◽  
Jun Peng Jia
Keyword(s):  
Degrees Of Freedom ◽  
Clamping Force ◽  
Compact Structure ◽  
Mechanical Calculation ◽  
Working Principle ◽  
Working Status ◽  
Clamping Device ◽  
Fixed Cylinder ◽  
Vibration Noise

Two-point floating clamping device, widely used in manufacturing field, can effectively ensure the same clamping force on different workpieces or different surfaces in one workpiece. But due to the application of unitary suspended articulated cylinder, traditional two-point floating devices have disadvantages such as poor working status, great impaction, vibration and noise. A kind of innovatively designed two-point floating clamping devices, with rigidly fixed cylinder replacing unitary suspended articulated cylinder, is presented in this paper. To solve the problem of insufficient degrees of freedom, three different methods are applied. This device has significant advantages in compact structure, small impaction and vibration noise. Moreover, the working principle and mechanical calculation formulas are presented in this paper, which is instructive to the industrial field.

Green Manufacturing: a Pumpless Mechanical-Hydraulic Clamping Device Based on Wormgear and Crank-Slider Mechanism

2011 ◽  
Vol 201-203 ◽  
pp. 2254-2257 ◽  
Author(s):  
Yin Zhuo Bai ◽  
Guang Ju Si ◽  
Xin Li ◽  
Kang Min Zhong
Keyword(s):  
Green Manufacturing ◽  
The Self ◽  
Clamping Force ◽  
Power Sources ◽  
Mechanical Calculation ◽  
Speed Reducer ◽  
Working Principle ◽  
Oil Tank ◽  
Clamping Device ◽  
High Flexibility

Hydraulic transmission clamping device may cause environmental pollution due to the existing of fluid pump and open oil tank. A new-concept clamping device based on high flexibility of hydraulic is introduced in this paper. Without any pump and open oil tank, environments pollution is reduced to a very low level. The driving piston is actuated by combined wormgear and crank-slider mechanism, the clamping piston is driven by sealed fluid in the two cylinders. The self-locking wormgear provides continuous clamping force during machining without any added energy, and a pressure switch guarantees the safety of operation. There are many choices when we considering the power sources, it could be electrical motor with proper speed reducer or just manpower, which provide a rotation movement. The working principle and mechanical calculation formulas are presented in this paper, which is instructive to the industrial field.

Considerations on Designing Artificial Muscle Working at High Pressure

2012 ◽  
Vol 268-270 ◽  
pp. 1457-1463
Author(s):  
Li Chao Wang ◽  
Xiao Dong Wang
Keyword(s):  
High Pressure ◽  
Material Properties ◽  
Weight Ratio ◽  
Artificial Muscle ◽  
Force Output ◽  
Compact Structure ◽  
Small Power ◽  
Small Force ◽  
Working Principle ◽  
Contraction Angle

Artificial muscle is a new style of actuator with novel working principle, which owns the advantages of compact structure, high power-to-weight ratio, compliance and easy application. Pneumatic artificial muscle (PAM) is usually used in robotics, medical auxiliaries and other small force output occasions nowadays. However, it suffers problems of small power, hysteresis and poor repeatability. A kind of artificial muscle working at high pressure was researched. Different muscle styles are compared and MicKibben structure is selected while fluid media is determined. Furthermore, factors of geometry and material properties, which limit the ultimate pressure, are analyzed. Formulas and simulations verify the influence of limitation and help to calculate key parameters of 18MPa artificial muscle. Data show that it is possible in theory to design high pressure artificial muscle by overall consideration of initial diameter, initial contraction angle and material properties, initial length only influent the stroke.

scholarly journals Conceptual mechanical design of antagonistic variable stiffness joint based on equivalent quadratic torsion spring

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042094129
Author(s):  
Jishu Guo
Keyword(s):  
Degrees Of Freedom ◽  
Modular Design ◽  
Angular Displacement ◽  
Variable Stiffness ◽  
Human Robot Interaction ◽  
Design Calculation ◽  
Robot Arm ◽  
Compact Structure ◽  
Torsion Spring ◽  
Stiffness Characteristics

The variable stiffness joint is a kind of flexible actuator with variable stiffness characteristics suitable for physical human–robot interaction applications. In the existing variable stiffness joints, the antagonistic variable stiffness joint has the advantages of simple implementation of variable stiffness mechanism and easy modular design of the nonlinear elastic element. The variable stiffness characteristics of antagonistic variable stiffness joints are realized by the antagonistic actuation of two nonlinear springs. A novel design scheme of the equivalent nonlinear torsion spring with compact structure, large angular displacement range, and desired stiffness characteristics is presented in this article. The design calculation for the equivalent quadratic torsion spring is given as an example, and the actuation characteristics of the antagonistic variable stiffness joint based on the equivalent quadratic torsion spring are illustrated. Based on the design idea of constructing the antagonistic variable stiffness joint with compact structure and high compliance, as well as the different design requirements of the joints at different positions of the multi–degrees of freedom robot arm, nine types of mechanical schemes of antagonistic variable stiffness joint with the open design concept are proposed in this article. Finally, the conceptual joint configuration schemes of the robot arm based on the antagonistic variable stiffness joint show the application scheme of the designed antagonistic variable stiffness joint in the multi–degrees of freedom robot.

A Theoretic Study on Cam-Clamping Device

2011 ◽  
Vol 295-297 ◽  
pp. 1536-1539 ◽  
Author(s):  
Yuan Chao Deng
Keyword(s):  
Simple Structure ◽  
Theoretical Study ◽  
Low Cost ◽  
The Self ◽  
Clamping Force ◽  
Locking Mechanism ◽  
Different Types ◽  
Cam Profile ◽  
Clamping Device ◽  
Selection Of

A theoretical study has been made on the cam-clamping device. In this article, we consider specifically the calculations of cam geometry, calculations of clamping force and clamping torque, conditions for self-locking, and conditions for contact strength. Machine fixtures are essential in the process of mechanical manufacturing. There are many different types of fixtures, such as manual jig, pneumatic clamps, hydraulic fixtures, electric fixtures, etc. There are also many ways of clamping, such as incline clamp, screw clamp, eccentric circle clamp, hinge clamp [1], among which the eccentric circle clamp finds wide applications, especially in fast-clamping devices. Although the circular eccentric fixture possesses the advantages of simple structure, convenient manufacturing, and low cost, it suffers the drawbacks of small clamping force, short clamping-surface travel distance, and unreliable self-locking mechanism. The cam-clamping device discussesed in this article involves replaceing the eccentric circle with a cam, as shown in Fig. 1. The cam profile curve can be designed according to any requirements. The advantages of this replacement are obvious, in addition to preserving the advantages of the circular eccentric fixture, the cam-clamping can be designed according to the actual needs of clamping paths and selection of the appropriate cam profile to improve the self-locking.

scholarly journals Working and Limitations of Cable Stiffening in Flexible Link Manipulators

2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
Rahul Dixit ◽  
R. Prasanth Kumar
Keyword(s):  
Energy Consumption ◽  
Finite Number ◽  
Degrees Of Freedom ◽  
Control Algorithms ◽  
Flexible Link ◽  
The Past ◽  
Working Principle ◽  
Reduce Energy Consumption ◽  
High Flexibility ◽  
Special Control

Rigid link manipulators (RLMs) are used in industry to move and manipulate objects in their workspaces. Flexible link manipulators (FLMs), which are much lighter and hence highly flexible compared to RLMs, have been proposed in the past as means to reduce energy consumption and increase the speed of operation. Unlike RLM, an FLM has infinite degrees of freedom actuated by finite number of actuators. Due to high flexibility affecting the precision of operation, special control algorithms are required to make them usable. Recently, a method to stiffen FLMs using cables, without adding significant inertia or adversely affecting the advantages of FLMs, has been proposed as a possible solution in a preliminary work by the authors. An FLM stiffened using cables can use existing control algorithms designed for RLMs. In this paper we discuss in detail the working principle and limitations of cable stiffening for flexible link manipulators through simulations and experiments. A systematic way of deciding the location of cable attachments to the FLM is also presented. The main result of this paper is to show the advantage of adding a second pair of cables in reducing overall link deflections.

A Practical Fuzzy Adaptive Control Strategy for Multi-DOF Parallel Robot

2013 ◽  
Vol 347-350 ◽  
pp. 661-665 ◽  
Author(s):  
Wei Meng ◽  
Zu De Zhou ◽  
Quan Liu ◽  
Qing Song Ai
Keyword(s):  
Degrees Of Freedom ◽  
Fuzzy Inference ◽  
Control Strategies ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Medical Rehabilitation ◽  
Position Tracking ◽  
Tracking Accuracy ◽  
Compact Structure ◽  
Fuzzy Adaptive

Multiple Degrees of Freedom (DOF) parallel robots possess the advantages of being compact structure, great stiffness, stability and high accuracy, so such platforms have been widely used in application areas as diverse as the spacecraft motion simulators, radio telescopes, and medical rehabilitation devices. In this paper, after giving a brief review on the control strategies for parallel robot, a 6-DOF robot system for medical purposes based on simulation as well as real environment is established. In order to improve the position tracking accuracy for such objects with time-varying and nonlinear parameters, a practical fuzzy adaptive controller is designed based on the kinematics of parallel platform, where fuzzy inference units are utilized to modify the PID parameters in real-time by using the position feedback from the robot actuators. Finally, both virtual and actual experiment results demonstrate that the proposed algorithm is able to effectively reduce the position tracking errors compared with the traditional PID controller, and the reliability and feasibility of such parallel robotic system can also be guaranteed.

scholarly journals A self-aligning end-effector robot for individual joint training of the human arm

2021 ◽  
Vol 8 ◽  
pp. 205566832110198
Author(s):  
Sivakumar Balasubramanian ◽  
Sandeep Guguloth ◽  
Javeed Shaikh Mohammed ◽  
S Sujatha
Keyword(s):  
Degrees Of Freedom ◽  
Simple Algorithm ◽  
Optimization Procedure ◽  
Estimation Procedure ◽  
Compact Structure ◽  
End Effector ◽  
Human Arm ◽  
Robotic Devices ◽  
The Individual ◽  
Human Limb

Aim: Intense training of arm movements using robotic devices can help reduce impairments in stroke. Recent evidence indicates that independent training of individual joints of the arm with robots can be as effective as coordinated multi-joint arm training. This makes a case for designing and developing robots made for training individual joints, which can be simpler and more compact than the ones for coordinate multi-joint arm training. The design of such a robot is the aim of the work presented in this paper. Methods: An end-effector robot kinematic design was developed and the optimal robot link lengths were estimated using an optimization procedure. A simple algorithm for automatically detecting human limb parameters is proposed and its performance was evaluated through a simulation study. Results: A six-degrees-of-freedom end-effector robot with three actuated degrees-of-freedom and three non-actuated self-aligning degrees-of-freedom for safe assisted training of the individual joints (shoulder or elbow) of the human arm was conceived. The proposed robot has relaxed constraints on the relative positioning of the human limb with respect to the robot. The optimized link lengths chosen for the robot allow it to cover about 80% of the human limb’s workspace, and possess good overall manipulability. The simple estimation procedure was demonstrated to estimate human limb parameters with low bias and variance. Discussion: The proposed robot with three actuated and three non-actuated degrees-of-freedom has a compact structure suitable for both the left and right arms without any change to its structure. The proposed automatic estimation procedure allows the robot to safely apply forces and impose movements to the human limb, without the need for any manual measurements. Such compact robots have the highest potential for clinical translation

Reconfigurable Clamping Device Based on Multi-Function Link and Hydraulic Cylinder With Built-In Piston Rod

2009 ◽  
Author(s):  
Lufei Zhou ◽  
Kangmin Zhong ◽  
Xiaoming Sheng
Keyword(s):  
Hydraulic Cylinder ◽  
Clamping Force ◽  
Line Contact ◽  
Geometric Shapes ◽  
Variable Volume ◽  
Piston Cylinder ◽  
Type Variable ◽  
Clamping Device

Reconfigurable clamping devices based on multi-function linkage and rod-less piston cylinder by fluid transmission were introduced. Their working principles have been introduced, and the relevant mechanics calculation formulas were presented. In these devices, rod-less piston cylinder was used as a drive, while multi-function bars and wheels with simple and similar geometric shapes as the basic components. The needs for the clamping of workpieces with different sizes or shapes and requirements for the line-contact or face-contact clamping can be meet by changing the shapes of the basic components and the locations, meanwhile great clamping force can be provided. Due to the rapid reconstruction, the demands of multi-type, variable-volume and short periods can be satisfied.

Two-Position and Highly-Efficient Clamping Device Based on Lever-Toggle Force Amplifier Driven by Pneumatic Muscle

2011 ◽  
Vol 201-203 ◽  
pp. 2841-2845
Author(s):  
Lin Lu ◽  
Ming Di Wang ◽  
Kang Min Zhong
Keyword(s):  
Production Efficiency ◽  
Simple Structure ◽  
Power Transmission ◽  
Compressed Air ◽  
Clamping Force ◽  
Pneumatic Muscle ◽  
Pneumatic Muscles ◽  
Output Force ◽  
Design Idea ◽  
Clamping Device

The clean compressed air is taken as power transmission medium in pneumatic clamping devices, and when cutting after clamping the workpiece, the energy are not consumed any more. So it can be said that it is a green clamping technology. However, a low pressure of pneumatic driving makes a lot of pneumatic fixtures too bulky in size.A new innovation design idea of clamping mechanism based on pneumatic muscle and the eternallever-toggle force amplifier is described in this paper, in which the pneumatic muscle is instead of traditional rigid cylinder. The pneumatic muscle has some features such as extremely simple structure, good flexibility, the big ratio of output force and diameter/weight, etc. Thus, this device can get much greater clamping force on the condition of reducing the size and weight of the structure definitely. In addition, using two pneumatic muscles alternately, it can enable the time of processing a workpiece to overlap with the time of unloading another workpiece, and which can improve the production efficiency significantly.

Design and human–machine compatibility analysis of Co-Exos II for upper-limb rehabilitation

2019 ◽  
Vol 39 (4) ◽  
pp. 715-726
Author(s):  
Leiyu Zhang ◽  
Jianfeng Li ◽  
Shuting Ji ◽  
Peng Su ◽  
Chunjing Tao ◽  
...  
Keyword(s):  
Upper Limb ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Compact Structure ◽  
Vertical Movements ◽  
Content Type ◽  
Upper Limb Rehabilitation ◽  
Compatibility Analysis ◽  
Configuration Synthesis ◽  
Limb Rehabilitation

Purpose Upper-limb joint kinematics are highly complex and the kinematics of rehabilitation exoskeletons fail to reproduce them, resulting in hyperstaticity and human–machine incompatibility. The purpose of this paper is to design and develop a compatible exoskeleton robot (Co-Exos II) to address these problems. Design/methodology/approach The configuration synthesis of Co-Exos II is completed using advanced mechanism theory. A compatible configuration is selected and four passive joints are introduced into the connecting interfaces based on optimal configuration principles. A Co-Exos II prototype with nine degrees of freedom (DOFs) is developed and still owns a compact structure and volume. A new approach is presented to compensate the vertical glenohumeral (GH) movements. Co-Exos II and the upper arm are simplified as a guide-bar mechanism at the elevating plane. The theoretical displacements of passive joints are calculated by the kinematic model of the shoulder loop. The compatible experiments are completed to measure the kinematics of passive joints. Findings The compatible configuration of the passive joints can effectively reduce the gravity influences of the exoskeleton device and the upper extremities. The passive joints exhibit excellent compensation effect for the GH joint movements by comparing the theoretical and measured results. Passive joints can compensate for most GH movements, especially vertical movements. Originality/value Co-Exos II possesses good human–machine compatibility and wearable comfort for the affected upper limbs. The proposed compensation method is convenient to therapists and stroke patients during the rehabilitation trainings.

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