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I have removed the following link, which seems to be broken: STEWART PLATFORM — Preceding unsigned comment added by 213.183.84.169 (talkcontribs) 18:17, May 22, 2005‎

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LME Hexapod link is down, has been down the last 6 months. I dont think it's coming back up. Sad to see it go. Here is a mirror I made of the site: http://fenn.dyndns.org/pub/www.i-way.co.uk/~storrs/lme/LMEHexapodMachine.html The archive.org copy is missing all of the .zip files. Please make mirrors of my mirror! A tarball of the website is available here: http://fenn.dyndns.org/pub/www.i-way.co.uk.tgz — Preceding unsigned comment added by 75.19.183.219 (talkcontribs) 02:00, December 11, 2006‎

Inverse Kinematics needs work

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In the 'Dynamics' section, it talks about how the inverse kinematics problem has a 'unique and simple solution', but fails to either disclose this solution nor provide a link to that solution. I'm not knowledgeable in this area, but I'm quite curious about said solution. — Preceding unsigned comment added by 142.167.187.6 (talkcontribs) 20:32, December 18, 2007‎

Given a platform with 6 nodes, the location of those nodes can be changed from an arbitrary neutral position by translation and rotation. Once the spatial coordinates of the nodes in the desired position are known, you need only calculate the distance between the platform node and base node to find the required leg length. Once all legs are adjusted to the calculated length, the platform will be at the desired orientation. You can also calculate Forward kinematics iteratively by using an approximate position (often the last known). Involves the Jacobian matrix.
In return, I have a question about other ways to make a 6 DOF machine. If you look at some of the machines at http://prsco.com/ (the company I work for) they show some machines that generate the motion by altering the location of the base nodes, while the leg lengths are constant. Do these count as “Stewart Platforms”, or does “Stewart Platform” specifically move by changing leg length? — Preceding unsigned comment added by 64.140.222.126 (talkcontribs) 11:38, November 17, 2008

Incorrect chronology

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Isn't the chronology of the introduction dodgy? Who published in 56 and who in 65? — Preceding unsigned comment added by 64.246.146.251 (talkcontribs) 05:34, July 16, 2008

How annoying! I just lost due to a server error a long discussion about Stewart Platform kinematics, in an attempt to partially answer the first question on this talk page. -- foxkid (talk) 00:54, 4 August 2008 (UTC)[reply]

Axial shaft bearings, or actuator shaft rotation?

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I am trying to analyze the construction of the platform. It looks like slightly more than just actuators, common 2-axis universal joints, and the platforms are needed.

When the upper platform is rotated on the yaw / Z-axis in relation to the lower platform, apparently there also needs to be axial rotation bearings at either the top or bottom plate where the universal joint connects to the plate, to allow the actuator arms to twist as the plate rotates.

Though if hydraulic or pneumatic actuators are used, possibly the piston itself could rotate slightly inside the cylinder without need for axial bearings. Are the seals on hydraulic/pneumatic cylinders able to tolerate shaft rotation?

Can electromechanical actuators tolerate rotation of their shaft/body components?

-- DMahalko (talk) 06:45, 18 February 2015 (UTC)[reply]

Patent searching for Stewart Platform / 6DOF platform

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Patent Publication Country Description
2179605 Aug 27, 1985 GB Motion simulator
2306429 Dec 29, 1942 USA Device for instructing students in flying
2549916 Jul 25, 1985 FR An active joint has compliance (Dispositif d'articulation actif a compliance)
2687491 Feb 14, 1992 FR Vehicle simulator with a wide visual field and low moving masses (Simulateur de vehicule a grand champ visuel et faibles masses en mouvement)
2695783 Nov 30, 1954 USA Simulated aircraft
2802635 Aug 13, 1957 USA Flex jack
3083473 Apr 2, 1963 USA Space flight environmental simulator
3159968 Dec 8, 1964 USA Mounting structure for thrust devices
3288421 Mar 25, 1969 USA Movable and rotatable top
3295224 Jan 3, 1967 USA Motion simulator
3451146 Jun 24, 1969 USA Mechanical motion system
3577659 May 4, 1971 USA Motion simulator actuator joint
3597857 Aug 10, 1971 USA Ground based flight simulating apparatus
3645011 Feb 29, 1972 USA Motion system with three reciprocating
actuators for flight simulation
3752429 Aug 14, 1973 USA Three axis simulator
3952979 Apr 27, 1976 USA Isolator
4066256 Jan 3, 1978 USA Amusement ride
4164080 Aug 14, 1979 USA Basic simulator unit
4343610 Aug 10, 1982 USA Motion systems providing three or four
degrees of freedom
4507086 Mar 26, 1985 USA Turret shaker mechanism
4559014 Dec 17, 1985 USA Motion limiting systems
4753596 Jun 28, 1988 USA Motion simulator
4872363 Oct 10, 1989 USA Electric positioning apparatus
5028180 Sep 1, 1989 USA Six-axis machine tool
5179525 Jan 12, 1993 USA Method and apparatus for controlling geometrically simple parallel mechanisms with distinctive connections
5366375 Nov 22, 1994 USA Motion simulator
5401128 Mar 28, 1995 USA In a machine for cutting a material
5403238 Apr 4, 1995 USA Ride vehicle control system
5433608 Jul 18, 1995 USA Vehicle simulator and method for controlling
a vehicle simulator
5473990 Dec 12, 1995 USA Ride vehicle control system
5511979 Apr 30, 1996 USA Motion system including actuator assembly
5722897 Mar 3, 1998 USA Sensory simulator and editor and a method
of using the same
5740699 Apr 21, 1998 USA Wrist joint which is longitudinally
extendible
5931739 Aug 3, 1999 USA Fail-safe ride simulator
6039653 Mar 21, 2000 USA Apparatus, system and method for
experiencing motion
6077078 Jun 20, 2000 USA Motion simulator device with at least
three degrees of freedom
6094180 Jul 25, 2000 USA Gimbal-mounted virtual reality display system
6634885 Oct 21, 2003 USA Flight simulators
7033177 Apr 25, 2006 USA Motion simulator
7967688 Jun 28, 2011 USA Motion simulator
8151660 Apr 10, 2012 USA Three axes rotational motion-positioning
apparatus
8403673 Mar 26, 2013 USA Motion platform system
20150081100 A1 Mar 19, 2015 USA Method for calibrating kinematics

-- DMahalko (talk) 10:58, 10 March 2015 (UTC)[reply]