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Showing results for tags 'Linear Actuator'.
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I am getting close to the end of this long term build and it's time to share some pictures and a bit of the story. Even before I had finished putting together 10231, I decided I wanted a Crawler to go with it. Being a Technic fan it had to at least drive around and lift the launch platform and shuttle. Those two basic goals spawned a project that has lasted a little over 2 years so far. Some ideas have stuck around since their inception, others were a bit optimistic (like building a peristaltic pump and hoping I could find a way to control the pneumatics hydraulically). February this year marked the 50th anniversary of when the two crawlers went into service, so recently there has been extra motivation to finish. The base equipment; - 16x M-motors (drive) - 4x L-motors (pneumatic jacking and leveling) - 4x IR Receivers (V1 as the V2s do not like driving multiple m-motors on a single channel) - 4x NXT servo motors (steering) - 4x RCX rotation sensors (measuring jacking level between truck and chassis) - 2x NXT bricks (one master and one slave. The master communicates with the Android Tablet and coordinates itself with the slave. Programmed in LeJOS) - 1x PF IR-Link sensor (link between master NXT and all PF motors) - 2x PF Battery boxes (with thermal overload removed) - 1x Android Tablet Future add-ons - Accelerometer (automatically detect the crawler is on a gradient and adjust the leveling to suit) Bricksafe folder is here: http://www.bricksafe.com/pages/OzShan/Crawler Firstly, a couple of my favorite reference pictures; The build itself started with the trucks, thinking that the pneumatics and LAs would dictate the scale. First proof of concept - build a coupling to give height, pitch, roll and yaw to the truck. The pneumatics need to be on their own gimbals too. The reinforced 2x2 rounds slide and rotate in the 4x4 macaroni's. It is on the limit of what will hold together without glue, but it does hold. The two 1x2 technic bricks at the base of the 2x2 column are helped a little by a string (not pictured) which runs up through the 2x2 rounds with the axle. Initial prototype of the drivetrain. I would have liked a higher ratio but there was just no room at this scale. When the gearbox was married with the truck chassis I had to juggle positions, so you will see in later pics the crown gears are facing in not out Best laid plans.... Marry studded and studless they said. It will be easy they said... Showing what will eventually be the steering between chassis and truck. The guide tube and pneumatic cylinders are all on gimbals with the pneumatics coupled together. The average height is preserved during any tilting. With prototypes sorted, it's time to bricklink some parts and quieten down the colour scheme! (thank you 42030 for providing 5L thin liftarms with axle hole in LBG color) You can see the relationship between "guide tube" and cylinders here. The pneumatic system was overhauled too many times to remember but this is what it arrived at. It is all controlled by the direction of the motor. Running forwards drives the pump. When running backwards, the lobes operate the pneumatic valves in series, letting small amounts of air escape each rotation. This lowers the chassis in a slow and controlled manner. The motor can be turned on or off and run in either direction at any time due to the valve timing. Early attempts with PF Servo and NXT servo just couldn't park the valve reliably and after a few operations I would hear a slow leak. I have been trying to keep up with the LDD but it's hard to stay motivated when I know I'm just going to have to suck it up and move over to LDraw if I want to include all the motors, pneumatics and LAs Works so far; (I'll make the files available if anybody would like them). I found LDD essential in the early days to plan ahead and simply find parts, but later on the build overtook it. Original 'box' pump. 1x PF XL motor, 4x 6L pumps running at 90 deg to each other. Very smooth but bulky. Flatter attempt in the same vein. The truck itself. The final design for the height control modules. I hope you enjoy the build so far. More pictures to come of chassis, steering, leveling and interior details. I'll leave it to others to decide what 'theme' it belongs to . -
Hi community, Is there a resource available for calculating the kinematics of the LA's? Some kind of a computerized solver where you put a initial condition, the stroke of a cylinder, the length, the final angle of rotation or degree needed? Or some program to solve or simulate the kinematics of 3 and 4 point linkage? For example, here's my problem: I want to raise a boom from -10 to 90 deg. What would be the ideal configuration in studless with large LA's? Unfortunately, my laptop can't handle SR3D; is there something else? Thanks