youtu.be/Q-UeYEpwXXU?si=Vo-Wj2Z2TuknCV-I

Usually, the robot only "knows" the position of each of…]]>

Usually, the robot only "knows" the position of each of its joints (encoder feedback), but people *using* the robot want to control it in Cartesian space (X,Y,Z,Rx,Ry,Rz)

Inverse Kinematics are used to convert a point in Cartesian coordinates into a set of joint angles that will put the last axis at a defined relationship to that point (the "defined relationship" is usually the Tool Center Point (TCP) of a tool attached to that last axis). It should be noted that for most kinematic hardware setups, there are multiple different joint combinations that achieve the same Cartesian coordinates, so some degree of disambiguation is required.

Forward Kinematics are the opposite -- taking the known translation/rotation of each axis (plus the TCP dimensions), the position of the TCP in Cartesian space can be determined.

]]>Thanks for a very helpful video]]>

Перший ресурс, який спадає на думку: https://www.youtube.com/@jamesbruton/search?query=ball

Thanks for a very helpful video

]]>I want to learn how to connect any cables/hoses/pathes etc on robots (especially on 6-axis robots, but I also interested in robots with extended axes or kinematic of any complexity). I can't find any book, video or article about it. Are there any links to the technical materials?

What bend radius can we use? Lenght?

Where is the best points to connect the cables on kinematic? Is this also true for the hollow wrist?

Where do I need to use clamps and where is it superfluous?

I do not know the exact answer to these questions and I usually make decisions based on experiments, experience and some special cases of the solution in the drawings, or along standard cables (if any). The task looks nontrivial even for computer modeling.]]>

[1] Inverse Kinematics of a Class of 6R Collaborative Robots with Non-Spherical Wrist

]]>Thank you in advance,

Looking forward to hearing from you.

this can be done in different ways, for example:

…]]>

this can be done in different ways, for example:

https://math.stackexchange.com…anes%20between,B%2BA)%2F2

note. that determines only part of the tool info (XYZ).

you still need to determine angles (ABC).

another option is to use some CAD software and create model of the tool (SolidWorks or whatever). then one can let that software generate report and from there one can extract info that corresponds to tool data

]]>I'm trying to make a dynamic model of pick-and-place manipulator called T-gantry.

This robot consists of two servo drives connected with tooth belt and end effector, on a cross base.

I've already assembled a dynamic model of an simplified model:

…]]>

I'm trying to make a dynamic model of pick-and-place manipulator called T-gantry.

This robot consists of two servo drives connected with tooth belt and end effector, on a cross base.

I've already assembled a dynamic model of an simplified model:

That is described by a motion equation:

(T1/r1) + (T2/r2) + F_ext = x'' * ( (J1/r1^2) + m + (J2/r2^2) ), where

T1, T2 - torques of servos

F_ext - external force

x'' - acceleration of the mass

J1, J2 - moments of inertia of servos

m - mass

r1, r2 - radii of the pulleys.

Now I want to assemble a two equation model describing movement of end effector, where

OUTPUT = acceleration in axis x and y, i.e. : x'' and y''

INPUT = torques T1 and T2

I don't think and don't claim that you're wrong. I just went step by step setting up the DH table according to the DH instructions.

The difference in calculations was only because of what was considered as…]]>

I don't think and don't claim that you're wrong. I just went step by step setting up the DH table according to the DH instructions.

The difference in calculations was only because of what was considered as variable value in th2 and th3. Because, the way I approached, in the DH tables these values had constant part (offset). For example, var2 = var1+90° is still a variable, but if var1 belongs to a range [-30°, +30°], then var2 will have a different range [60°, 120°] . That is why there was a difference.

Your posts were very helpful to me.

We can consider this thread closed.

https://www.chegg.com/homework…tand-millions-c-q90777648]]>

Hello guys. Has anyone ever researched the method to use only one 6-axes IMU to obtain the sway angles of the suspended payload to a quadcopter? As shown in the figure, the angle "α" is rotated about world-coordinate…]]>

Hello guys. Has anyone ever researched the method to use only one 6-axes IMU to obtain the sway angles of the suspended payload to a quadcopter? As shown in the figure, the angle "α" is rotated about world-coordinate x-axis, and the β is then rotated about the new y-axis. The payload can rotate about the rope simultaneously. Many thanks.

]]>A frame is a coordinate system.

A tool frame is a coordinate system attached on the end of the link chain. It is affected and moved by robot joints in relation to the world or…]]>

A frame is a coordinate system.

A tool frame is a coordinate system attached on the end of the link chain. It is affected and moved by robot joints in relation to the world or base.

A world frame (ABB) is a stationary frame of your choice, standard position(ABB) at the base of the robot

A TCP is a Tool Center Point - So, strict speaking: point on the center of the tool. Where that center is (center of mass, center of shape, center of axle) is up to you. Most people use TCP as term for a tool frame. So, this term is used wishy washy.

Also there are no real standards for terms.

The robot reference frames are stored in base_data[x], where x is the number of base frame. So you have to align one of the base frames to your path planning frame and are done.

The same with the tool frame, they are stored in the variable…]]>

... Now, if we limit the discussion to 3DOF (XYZ), it gets simpler -- you simply have to ensure your reference frames are aligned between the software and reality, and your units are correct. It's not hard to create a simplistic script to convert a series of XYZ points into a string of robot commands....

The robot reference frames are stored in base_data[x], where x is the number of base frame. So you have to align one of the base frames to your path planning frame and are done.

The same with the tool frame, they are stored in the variable tool_data[x].

But you always need an orientation for every position, you can set it to a constant value.

Activating a tool, or base frame is done by the command

Bas(#base, x)

Bas(#tool, x), where x is the number of the tool or base.

]]>Once upon a time I had a Prof. that told us when he…]]>

Anyway, multiplication of two vectors are mathematical basics. May be it will be extremely hard to follow that paper, if you don't know the basics.😉

Once upon a time I had a Prof. that told us when he started to study mechanical engenieering he realized that you need very much mathematic skills, so he stopped studying mechanicals and started to study mathematics after finishing that he continued with mechanics.

]]>RHR, from everything I could determine. Just has the World frame rotated +90deg around Z compared to Fanuc, ABB, or KUKA, relative to the physical base. So Y+ is "forward" instead of X+.]]>

@SkyFire

Is Kawasaki LHR or RHR?

RHR, from everything I could determine. Just has the World frame rotated +90deg around Z compared to Fanuc, ABB, or KUKA, relative to the physical base. So Y+ is "forward" instead of X+.

]]>