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Showing results for tags 'skid-steer'.
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[TC22] Mini RC Tracked Loader
SaperPL posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
So I've been contemplating what to build for the contest as the volume restrictions is something that should fall exactly in my area of expertise, but with RC allowed, it got a bit complex. To fully handle a crane or excavator you need 5 or 6 motors, so either two hubs or something like buwizz 3.0 which supports 6 motors, and I'm not really sure if I'll be able to fit all that perfectly within the specified volume while not making it a messy build. So I decided to stick to stuff that I can power with a single hub, and I love the ease of use of physical remote from CADA so I ended up deciding to go with a tracked vehicle + two mechanical functions, so after looking at multiple options I decided to pick a tracked skid-steer loader - a bobcat: I like this one because it has an interesting geometry of the arms, which I expect to be there in order to prevent the bucket getting closer to the cab while the arms are getting raised. I yet have to test this theory. Here's a concept / design so far: I tested the geometry of the arm against keeping the bucket at same angle while the arm is changing its angle, assuming the lever holding liftarm over the arm has fixed angle, and it works more or less. I don't have a bucket yet, and I've got to figure out the driving connection for it that has a significant gear reduction as well as it should have some safety like clutch gear, but I'm not sure if it is a good idea considering weight of the bucket. I'm not 100% sure that I'll be able to go with the design of the arm that is supported by that liftarm to move forward/keep horizontal position of the bucket, especially because of the requirements for the bucket tilt lever connection to the motor. Additional note here is that the tracks are shaped in a way that rear gears one exactly above each other because I couldn't achieve optimal track tension in other configurations and also I would have to make more space for the attachment of linear actuators behind the tracks and it would complicate the base structure. Finally I might end up with arms hitting the cab, so maybe I'll have to move them by 1 stud to the sides, which would made the proportions weird, but I don't think I'll be able to shrink the cab without showing a mess of cables. -
[MOC] Heavy Duty Skid-steer Loader
JLiu15 posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Experimental MOC combining Mindstorms Robot Inventor and Control+. Features drive, backing alarm, arm elevation, bucket tilt, and a pallet fork alternate attachment with manually adjustable fork width. Functions/features: Drive (4x medium angular motors; 1 per wheel) Arm elevation (C+ L motor) Bucket tilt (C+ L motor) Manually adjustable fork width (on pallet fork attachment) Backing alarm Ever since I had heard that the new Mindstorms Robot Inventor is cross-compatible with Control+, I made a goal of creating a MOC combining them. A skid-steer loader seemed like a good subject to start for me - I wanted the drive to be as direct as possible, without connecting the wheels on one side with gears to a single motor. This meant 4 motors for the drive and 2 motors for each of the arm functions - perfect for the 6 ports on the Robot Inventor hub. The building process started with a base for the model - 4 medium angular motors each connected to a single wheel via a planetary hub. The motors were sandwiched between 2 11x15 Technic frames, creating a robust structure. The Robot Inventor hub is placed behind this part, and the C+ L motors for the arm functions are located above the drive motors. The chassis was kept as flat as possible with everything kept low to lower the center of gravity. Just in front of the Robot Inventor hub are two gear trains that transfer drive to the arm elevation and bucket tilt functions. Thanks to the use of planetary hubs, the model had plenty of torque and is able to climb some steep slopes without any issues, as shown in the video. Aesthetics wise, the model has a simple yellow/black color scheme. My original inspiration for this model was the CASE SV340, so the color scheme had some resemblance to that. Building the bodywork was quite discouraging at first due to it feeling like a building a box on wheels, but the model's looks really came together as the arms and rear body panels were installed. I also used plates and tiles to cover up bare pin holes and make the model look more finished, especially on the roof but also in other areas like the front windshield pillars and the top of the arms. Additionally, the model includes a handful of new 2021 panels, such as the small 3L curved panel and the 3x7 flat panel. As for accessing the Robot Inventor hub, there are 2 discreet switches in the bottom rear of the model that press the power and Bluetooth buttons on the hub. As everything is done from my iPad after powering it on and connecting it via Bluetooth, I don't have to look at the screen or press the left/right buttons. The status sounds from the hub allow me to know if the hub is powered on, connected, or powered off. As for controlling the model, I created a simple control profile in the Robot Inventor app using its code blocks. Two sliders control drive, and the arm functions are controlled using buttons. Additionally, a backing alarm sounds when driving in reverse. This feature is only controlled by the left slider, as I found that controlling it with both will essentially cause two backing alarms to play over each other. One issue I had is that the drive motors often don't start all at once - there'd be a noticeable delay in one or more of the motors. The C+ motors for the arm functions, however, work fine. I'm not sure what causes this, but this will definitely be something to consider for my next Robot Inventor/C+ hybrid MOC. Overall, I'm decently satisfied with this MOC. It was an interesting experiment in combining Robot Inventor and C+ that largely went according to plan. As someone who builds Technic MOCs, the new Robot Inventor hub is far better than the EV3 brick - it's got much better form factor (it's even a stud lower than the C+ hub), uses rechargeable batteries and is therefore much lighter, and has 6 ports that aren't restricted to motors or sensors. The only downsides IMO are the color (as teal doesn't blend well with most colors in Lego Technic) and the bright screen, but that can be easily covered up as I've done here. I definitely have plans for more Robot Inventor/C+ hybrids in the future, whether that be a Robot Inventor hub MOC with C+ motors or a C+ hub MOC with Robot Inventor motors. Photos: Video: