Direct kinematic solution of a Stewart platform

Nanua, P.; Waldron, Kenneth J.; Murthy, Vaibhav

doi:10.1109/70.59354

Cited by 289 publications

(88 citation statements)

References 5 publications

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“…It has some difference from the 6-dof Stewart platform. 7) In fact in the Stewart platform the six actuators are linked to the superior plate by six joints, while only three joints are used in this one. All the joints of the structure, of the upper plate, R, S and T, and of the lower plate, A, B, C, D, E and F, are spherical ones.…”

Section: The Kinematic Designmentioning

confidence: 99%

Design of a Parallel Robot Actuated by Shape Memory Alloy Wires

Raparelli

Zobel²,

Durante³

2002

Mater. Trans.

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In this paper the design and the manufacture of a 3-dof (degrees of freedom) robot driven by shape memory alloys (SMA) is presented. This robot has a parallel structure including a fixed plate and a moving plate. The plates are linked together by 3 SMA wires and a mechanical spring is located in the central part. Possible applications are the control devices to orient a mirror, a sample under a microscope or to orient the head of a micro snake like robot. The paper explains the kinematic model, the mechanical design and the control system of the robot. The feedback signals of the closed loop control system are the displacements of the SMA joints located on the moving plate, measured by three conductive potentiometers. The control system is P.C. based. The SMA actuators are driven by Nitinol wires of a diameter of 0.15 mm. The robot takes up a cylinder with a diameter of 100 mm and a height of 180 mm. A prototype of the robot has been manufactured and some experimental tests were carried out. These tests are carried out both using a simple test bed made by a SMA wire and a pulley, and using the prototype itself. The step response of a single SMA wire and the trajectory control to describe a circle in the prototype are also shown as validation tests of the robot. The results of the experimental validation show the feasibility of this design, but particular attention has to be paid to the machining and to the assembly.

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Section: The Kinematic Designmentioning

confidence: 99%

Design of a Parallel Robot Actuated by Shape Memory Alloy Wires

Raparelli

Zobel²,

Durante³

2002

Mater. Trans.

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“…The direct kinematics of parallel mechanisms is commonly a complicated problem to solve (Lenarcic and Wenger 2008); one analytic solution was proposed by (Nanua et al 1990), who found a closed form solution for a special form of the Stewart platform.…”

Section: Introductionmentioning

confidence: 99%

“…Parallel structures, such as the Stewart platform (Stewart 1965), are well known mechanisms characterized by two plates connected each other by six links (or legs) through spherical joints. The Stewart platform, thanks to these properties, is commonly used as actuator in many fields where high precision movements and high pay loads are required: high precision manipulators (Merlet 2006), radio telescope orientation (Su et al 2003), aircraft and vibration simulators (Nanua et al 1990), machine tools ), etc. Parallel structures were also introduced for sensing force and torque (Sorli and Pastorelli 1995); in these cases, the legs of the platform are represented by uniaxial force sensors and the device geometry is fixed; this means that no relative displacements between the parallel plates may occur.…”

Section: Introductionmentioning

confidence: 99%

Multi-dofs MEMS displacement sensors based on the Stewart platform theory

Mura

2012

Microsyst Technol

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This work proposes a new detection strategy suitable for MEMS sensors with up to 6 degrees of freedom. Parallel structures based on the Stewart theory are commonly adopted as actuators in many fields such as high precision manipulators, aircraft and vibration simulators and machine tools; the same configuration was used here to define the kinematics of a displacement sensor in the microscale based on the optical detection. The algorithm for the estimation of absolute positions and orientations of the platform is presented. The described sensing approach considerably simplifies the platform architecture and design and introduces a promising solution for many MEMS sensors and devices.

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“…During each step of the cockroach robot, each leg lifts up and lays down in a certain sequence, which is called gait [4][5] . When some legs are lifted up, the standing legs will form a parallel robot [6][7] . Then, considering the instantaneous state, a cockroach resembles a parallel system with redundant DOF and its movement can be considered as a series of movements of redundant robots.…”

Section: Introductionmentioning

confidence: 99%

Kinematics analysis and experiment of a cockroach-like robot

Gao

Chen

2011

J. Shanghai Jiaotong Univ. (Sci.)

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This article describes the structure of the cockroach-like robot. Both kinematics and locomotion control are inspired by biological observations in cockroaches. Based on cockroach-like robot kinematics analysis, screw theory, and the production-of-exponential (POE) formula, this paper focuses on the inverse kinematics which uses Paden-Kahan sub-problems to obtain directly the displacement of joint angles. The forward kinematics derives the relationship between joint angles according to the natural restrictions. Then, by using the POE formula, it can deduce the body pose and realize online trajectory control and planning. Through simulation and experimentation, it is proved that the straight-line walking and turning gait algorithms have static stability and the inverse kinematics analysis of cockroach-like robot is correct.

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Direct kinematic solution of a Stewart platform

Cited by 289 publications

References 5 publications

Design of a Parallel Robot Actuated by Shape Memory Alloy Wires

Design of a Parallel Robot Actuated by Shape Memory Alloy Wires

Multi-dofs MEMS displacement sensors based on the Stewart platform theory

Kinematics analysis and experiment of a cockroach-like robot

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