7

Both the forward kinematics and inverse kinematics aren't too difficult, but always a little tricky for parallel manipulators like this one. Consider the configuration in this diagram. The forward kinematics first involve solving for the position of the joint where you hold the pen from each motor joint separately and then equating the two. $\begin{bmatrix}...


6

Efficiency isn't the right thing to compare due to various advantages and disadvantages of each type of wheel. Comparing the efficiency of the different types of wheels is like comparing apples and oranges. However, comparing speed and force can give a good comparison of the different types of wheels. Here is a table that offers a quick and simple ...


6

I have some experience with using mecanum wheels, both indoors and outdoors (on grass, sand and dirt no less). Obvious advantage is holonomic movement. Disadvantages are weight (commercially available wheels are ridiculously heavy) and cost. For a given tread material traction will be along the lines of 65-70% that of a regular wheel due to the smaller ...


5

Ball detection using vision is not extremely difficult, especially if the ball is easy to recognize. There are a lot of tutorials and blogs which give a detailed explanation on how to implement an algorithm to solve this problem: Raspberry Pi Ball tracking Using OpenCV on the Beagleboard to track an Aibo pink ball OpenCV Tutorial C++ - Color Detection & ...


4

A general IK solution is not possible for an arm with less than 6 joints. You can move the gripper to any point (within reach) but you can't completely control the orientation. If you fix the orientation, say fingers aligned with vertical axis (normal to the work surface), this should simplify the analytic solution. Using my Toolbox, and starting with the ...


4

If you say you're are stuck after values for the first two angles, you are probably trying an analytical approach. Try solving for IK using standard techniques Jacobian Pseudo Inverse or Cyclic Coordinate Descent. If you are looking for immediate solutions, use Peter Corke's Robotic Toolbox for MATLAB or KDL/TracIK in C++/Python to obtain the values.


4

The original manipulators referred to in that article were through-the-wall pantographs which moved radioactive materials without the human operator having direct contact with those materials. The end effectors of those manipulators did have direct contact with the materials - just not the human. Although the article is not specific about this, it seems ...


3

While originally creating this question I ended up finding an RC servo that can do this. HiTECH makes an RC servo (HS-785HB) that uses a muti-turn potentiometer rather than a standard rotary potentiometer is its position senor. This allow the servo to rotate 3.5 turns (1260 degrees!!!) while still maintaining positional control. It is pretty slow (almost ...


3

I think what you are seeing here is a decade advancement in microprocessor and robotic control technologies. By the time the second and third papers were written, in 2000 & 1998, the definition of 'task planning' had switched from static pre-planning to dynamic reactive planning. The difference in microcomputer speeds between 1990 and 1998 is enormous. ...


2

I had the same problem with the "Ultimate 4tronix Initio 4WD Robot Kit" - the motors make some noise, but do not start moving. I tried using 8 batteries instead of 6 (for higher voltage on the motor), that helped for one motor assembly, but did not work for the other. I disassembled the gear box, and found that several of the gears had small plastic bumps ...


2

Not to completely ignore your direct questions, but I think you are overthinking the problem. I don't believe any linkage math or even inverse kinematics are required. The main reason is that the set of actions that the robot must perform (10 different characters at 4 locations) is small and the workspace never changes (a plane that is fixed to the robot). ...


2

Short answer: No. Long answer: In how many dimensions you are defining 'any'? The best way to understand it is actually through math. Let's say you have a desired position $$p=\left[\begin{matrix}x\\y\\z\end{matrix}\right]$$ and an orientation $$\omega=\left[\begin{matrix}\chi\\\psi\\\zeta\end{matrix}\right]$$ in three dimensions. Now let's say we have a ...


2

If you have a situation where your motor can break your system, for a small DC motor then rather than relying on a solution which requires the software to detect the condition, instead add limit switches to prevent it running beyond a point by inserting a diode in series with the motor when the switch is activated. For BLDC motors or more powerful motors ...


2

I will assume that you going to make everything from scratch. For computing unit I would recomend to use STM32 microcontroller (use Discovery or Nucleo board) however if you have never programmed before Arduino would be simple but a bit less powerful. For testing when transmiter with big range is needless you can use bluetooth module (HC-05) this will ...


2

We need to be able to track 3 points, (sometimes called features), on a solid body to estimate its 6dof pose relative to the camera. Each has an estimated position in the 2D camera image. If you imagine having only two points visible on the object, you can rotate the object around the line (axis) joining the two points and the 2D position in the image ...


2

You might want to try a Non linear controller if you want disturbance rejection. But I will suggest you to fine tune your PID first. Now, back to non linear controls, you need to develop a very good mathematical model of the dynamics of your robot. You can use a scheduler controller: first linearize you plant at different operating points an design a ...


2

Warm blooded mammals and birds should be similar to humans as far as these sensors are concerned, amphibians and reptiles probably not. Here are some thermal signatures from sensors that are more sophisticated, but in any case should give you an idea of the difference in body temperature from the ambient background temperature, of some parakeets vs a lizard....


2

If you want to start programming a robot that's already built, the Scribbler 3 (S3) robot by Parallax, inc. is relatively affordable and comes already assembled. The programming relies on Blockly, a GUI-based programming language for robotics systems. I think it's popular in schools. If you're interested in something a bit more robust, why not look into the ...


2

In words, rather than code. Assume you have the path defined as a dense list of points. Find the point on the path closest to robot Draw a circle of radius R about that point, then find the point on the path where the circle cuts (usually the circle will cut between two points). The circle may cut the path multiple times, take the closest (along the path) ...


1

1) StackExchange is really not intended for the side-by-side mentoring it seems you are looking for. It is a good place to ask questions about specific problems you run into. 2) Python is not the programming language I would recommend for the real-time control needed for a robotics/mechatronics project, especially for a beginner. I recommend you start ...


1

You are using cheap MEMS components, they are typically prone to noise and drift. I don't know how you retrieve your angles but the sensors are giving you angular velocities and linear accelerations. Start by assessing the quality of these signals, and then see of this maps to your orientation. Typically there are two ways of computing orientation, either ...


1

An IMU gives you linear acceleration and rotational speed. It doesn't give a position. You can integrate the output of an IMU to get a linear position and angular orientation (the pose), but you need to choose initial speeds and positions. Typically, these choices are zero. If you decided to choose zero for your initial/default pose, then returning "home"...


1

Keeping tracking of (x,y) location would fall under state estimation. One fundamental method of state estimation is odometry.


1

Answering for others with the same question... I understand the OP has long since moved on I don't disagree with the others here, but have a different take. Direct answers to your questions (with an FTC Robotics perspective in mind): Just as you need at least a minimal computer to learn programming, you will need a at least a minimal robot to learn ...


1

I agree with what @PrestonRoy regarding the academic aspects. But, there is a big learning by doing component too. The earlier you start the better. Don't wait until you "know everything you need to". JOIN A ROBOTICS TEAM AND DIVE IN! In the process of doing, you will learn a lot about what robotics is what your need to learn. Last year my Freshman ...


1

I am a graduate student whose research is applied to robotics. I recommend: Linear algebra and Calculus Basic programming skills, learn arduino and another language Electronics courses - basic electric circuits Mechanics courses - statics and dynamics Control theory - as much as you can I would recommend pursuing a degree in either electrical engineering, ...


1

Typically a decision like this is made based on a list of design requirements. Have you listed these out? What do you expect the MCU to do? How many peripherals will you have? Since you have a deadline, I would focus first on getting something to work very quickly using a simple board such as an Arduino or teensy. This buys you two things: (1) You have ...


1

Physically Speaking No. Even most 6-axis (6DoF) industrial robots are unable to achieve full range of motion within their work envelope (or the work envelope is artificially restricted as more commonly seen). 7-axis (7DoF) robotic arms (commonly know as collaborative robots) have a much greater flexibility; They are generally only restricted by physical ...


1

In abstract theory, yes. You can have a body constrained to a path (1 Dof, forward and back along the path) and the path can loop through all possible orientations. Likewise you can constrain the body to a higher order manifold (a surface allows 2 or 3Dof depending on the physical mechanism of constraint). Mechanisms that we can build have other ...


1

Can you explain more about how the robot is to measure the height? It would seem to me like you could put the sensor at the top of a mast of known height $h$, looking down. Then the robot drives up to the block until the sensor feedback registers some distance other than $h$ (plus or minus some margin for noise, etc.) Once you are in position, the height ...


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