# Tag Info

### How has the Mars Exploration Rover (MER) has been working for 11 years if it was designed for 90 Sol?

There are 2 main reasons why the MER is still operating long after it's 90 Sol planned lifetime. The first is political, strategic, and can be summarized as 'Under promise, over deliver'. When a PI (...
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### Name of the linkage (or carriage) in video

The video shows 2 linear actuators driving a universal joint through ball and socket joints.
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### Robot mechanism parts names

This is called a Stewart platform. You can use any linear actuator type, hydraulic, pneumatic or electric.
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### High power jumping mechanism in small robots

Looks like it uses a propane powered ram to launch itself into the air. The end of the piston is visible in the back of the vehicle. This webpage states that source of power is battery and propane ...
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### What's the name of a robot manipulator construction with multiple thin arms joined together?

They are parallel manipulators. You may find chapters on parallel manipulators in robotics textbooks, for example, A Mathematical Introduction to Robotic Manipulation, useful. There are also a number ...
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### Different methods to determine DOF: Chebychev-Kutzbach-Grubler method vs. Screw method

I will try not to skip too many steps. Assuming a Global coordinate frame at the base and the arm is fully extended along the Y-axis of the base frame. Since SCARA has four joints, we will create ...
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### What is meant by the phrase "movement positional jitter"?

We can think of "jitter" as a fairly quick, fairly small perturbation upon the intended controlled behavior. A semi-quantitative design guideline (like "within 5%") needs a ...
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### Double/Triple inverted pendulum always on a cart?

There's no reason why you couldn't do it with a servo on the first pendulum, but the problem is very different. Instead of motion constrained on a line (cart), motion is constrained along an arc. The ...
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### Any books or web resources for robotics mechanical design?

You could look at three books. A Mathematical Introduction to Robotic Manipulation - S.Sastry, X.Li and R.Murray provides a theoretical foundation to the kinematics, dynamics and control aspects of ...
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### I need the scheme of iRobot Create 2

The schematic for the main board on the iRobot Create 2 is currently not available. It is advised to remove the plastic top cover before drilling into the electronics below. (This is good practice for ...
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### Sliding system basic question

This is a great problem to hone mechanism design skills on. There is a set of dimensions for which this mechanism works fine. The condition for this is that the contact of each rod & hole, ...
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### I need help figuring out what motor is used in this design

This looks to me like a linear pneumatic actuator. Pneumatic cylinders can be very fast acting, depending on the air pressure on hand, but they can be hard to control at any position other than their ...
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### What is the front mechanism of this robot's track called?

They seem to be called 'flippers' in most of the literature. This review of the iRobot 310 SUGV on Army Technology notes that: The 310 SUGV has an overall length of 76.1cm and width (flippers on) ...
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### Can somebody explain how these forward kinematics matrix equations were formulaed?

It looks (to me) like there's a typo in that answer. The approach is to recognize that you have to wind up at the same point, whether you get there via the left arm (d->e->blue dot) or the right arm (...
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### How can I attach an arm to a double-flat drive stepper motor?

You can use a D or Double D shaped shaft collar/coupler. Or obtain a Double D shaped punch, depending on the design of the piece you are attaching to the shaft.
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### Controlling Actuated Robot Hand in Underactuated Manner

I don’t think underactuated is the proper term. You are trying to control multiple actuators with a single DOF. That is redundancy resolution. I have used the Simplex Method to compute stable ...
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### How to seal a threaded rod so I won't lose oil?

Have you considered putting the motor inside the same oil-filled box as the part that needs to move? Many electric motors -- such as the coolant motor in practically all household refrigerators -- ...
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### Design a robot that can apply hot glue to paper

The problem I see is that after a while of holding the trigger, you have to let go of the trigger and then squeeze again. This is because the trigger has advanced the stick of glue as far as the ...
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### How does this end effector work?

The actuator has two raceways cut into it. One is a screw thread, and engages with a rotary screw nut that is turned by a motor. Turning the nut moves the actuator linearly. The other is a spline ...
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### Wall-E Legs mechanism

This is an appropriate question over at movies SE, but even here its probably interesting. Wall-Es character is definitely an interesting one, very dynamic, anthropomorphic, and modelled quite ...
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### Why do we say a robotic arm have 2 dof even though the two joints rotates along the same axis?

The degrees of freedom of a serial manipulator equals its number of joints. A more general definition can be found on Wikipedia. It is about being able to describe the state (configuration) of the ...
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### How to choose a servo motor for solar tracking mechanism?

Most solar tracking rigs only move along one axis because the efficiency savings from moving along 2 doesn't make up for the energy losses of having 2 motors. If you're just doing this for fun, then ...

### How to choose a servo motor for solar tracking mechanism?

Servo 1. Referring to your diagram, first consider the tilting part at the top. Imagine a line connecting its bearings. It will tilt (rotate) about that axis. The weight (force due to gravity) of the ...
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Look into fishing line. It rests quite comfortably on spools, can be quite strong, is applied where weight is a concern, and is readily available (although I don't know anything about its stretch). A ...
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I've used Spectra® braided fishing line for a cable driven robot hand. (I believe there are many similar products by other brands). I think it would probably work for your application too. Steer ...
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### How should I create a Pangolin (Armadillo) structure?

I would work backwards, looking at the design when it is closed. From that, you'll see how much larger each piece needs to be than the one below. Each piece is probably connected to the one below it ...
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### How do I calculate the direction robot is facing, pose from velocity and yaw rate?

Close. A simple solution is to first track the heading over time using the yaw rate sensors. If you're getting measurements every $\delta t$ seconds ... $$H(t+1) = H(t) + Yaw(t)*dt$$ The, you ...
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### Rotating two things on the same axis

It's called a sleeve bearing if you intend for the shafts to rotate relative to each other or a bushing if you intend for the shafts to move axially relative to each other. They generally look pretty ...
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### How to transfer motion between these two parts?

I believe what you are looking for is a 4 bar linkage. When opposite links are equal in length, they stay parallel.
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### Connecting two servo motors to drive one shaft

One bigger servo is better. You can just hook them both to the same shaft. If you give them the same command, they will fight each other a bit and waste some energy but should work. To improve ...
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