Modal space decoupled controller for hydraulically driven six degree of freedom parallel robot

Ogbobe, Peter O.; Ye, Zhengmao; Jiang, Hongzhou; Yang, Chifu; Han, Junwei

doi:10.1109/icmee.2010.5558548

Cited by 3 publications

(2 citation statements)

References 8 publications

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“…At neutral pose the body axes {p} attached to the moving platform are parallel to and coincide with the inertial frame {B} fixed to the base with its origin at the geometric centre of the base platform. Kinematics and dynamics analysis of the 6 DOF parallel mechanisms has been well established and can be found in several literatures [9][10][11][12][13].…”

Section: Six Degrees Of Freedom Pm Kinematicsmentioning

confidence: 99%

Modal Space Controller for Hydraulically Driven Six Degree of Freedom Parallel Manipulator

Ogbobe¹,

Okoye²

2022

int. j. eng. mgmt. res.

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This paper presents the Modal space decoupled control for a hydraulically driven parallel mechanism has been presented. The approach is based on singular values decomposition to the properties of joint-space inverse mass matrix, and mapping of the control and feedback variables from the joint space to the decoupling modal space. The method transformed highly coupled six-input six-output dynamics into six independent single-input single-output (SISO) 1 DOF hydraulically driven mechanical systems. The novelty in this method is that the signals including control errors, control outputs and pressure feedbacks are transformed into decoupled modal space and also the proportional gains and dynamic pressure feedback are tuned in modal space. The results indicate that the conventional controller can only attenuate the resonance peaks of the lower eigenfrequencies of six rigid modes properly, and the peaking points of other relative higher eigenfrequencies are over damped, The further results show that it is very effective to design and tune the system in modal space and that the bandwidth increased substantially except surge (x) and sway (y) motions, each degree of freedom can be almost tuned independently and their bandwidths can be increased near to the undamped eigenfrequencies.

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Section: Six Degrees Of Freedom Pm Kinematicsmentioning

confidence: 99%

Modal Space Controller for Hydraulically Driven Six Degree of Freedom Parallel Manipulator

Ogbobe¹,

Okoye²

2022

int. j. eng. mgmt. res.

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“…A vibration test rig is used to simulate the vibration environment of high-speed railway, and dynamic parameters of the specimen are studied by experiments [5], [6]. In the EHST, the number of hydraulic cylinders is greater than the degree-of-freedom (DOF), and the redundant degrees of freedom will cause coupling among the branches [7], [8]. Reducing the coupling among branches through decoupling is considered to be necessary in order to improve the motion flexibility of the EHST.…”

Section: Introductionmentioning

confidence: 99%

Modal Space Feedforward Control for Electro-Hydraulic Parallel Mechanism

Shen

Zang

et al. 2019

IEEE Access

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As a parallel mechanism with six-degree-of-freedom, an electro-hydraulic shaking table is endowed with strong coupling characteristics among different degree-of-freedoms. When the electrohydraulic shaking table moves to one direction, there will be some unnecessary related motions in other directions, which will affect the tracking accuracy. The kinematics model, the dynamic model, and the electro-hydraulic model are all established based on analyzing the components and working principles of the electro-hydraulic shaking table. After that, a modal space controller is built on the basis of a threevariable feedback controller by relying on the designed modal space matrix on the premise of modal control theory. In this regard, a multiple-input multiple-output system with strong coupling within the physical space is transformed into a set of single-input single-output systems independent from each other within the modal space. Moreover, the accuracy of vibration control can be improved by introducing a discrete feedforward controller. It is evident from the experimental results that the proposed control strategy can effectively improve the accuracy of vibration control.INDEX TERMS Electro-hydraulics, parallel mechanism, vibration control, coupling, modal space control.

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